sexstories.com
Most Read Sex Stories
-
Stacey returns by Biglad80085
Rated 93.9%, Read 28326 times, Posted Wed 28th of November 2012
Fantasy , Cum Swallowing, Job/Place-of-work, Young -
My Best Friend's Step-Sister by ChildishFanbino
«When my best friend is asleep, his step-sister seduces me.»
Rated 86.8%, Read 28326 times, Posted Mon 10th of April 2017
Fiction , Interracial, Teen, Teen Male/Teen Female -
FLIGHT 247 LOST BOYS CHAPTER 3 by boys in the hood
Rated 88.5%, Read 28323 times, Posted Sat 5th of March 2011
Fiction , Boy / Boy, First Time, Masturbation, Oral Sex -
Lawan, the right Thai at the right moment by mystyque
«Back when I was in Pattaya, I fucked a ladyboy, and told XNXX all about it. But something else happened as well. This is that very story.»
Rated 86.2%, Read 28323 times, Posted Thu 31st of May 2018
True Story , Asian, Hardcore, Interracial, Male/Female, Male/Teen Female, Teen, Young -
Dad's friend John by mazeyj
«an unexpected cock session»
Rated 78.7%, Read 28323 times, Posted Wed 9th of August 2017
Diary , Gay, Mature -
I meet my new nephew by Hot Bi Widow
Rated 89%, Read 28323 times, Posted Mon 31st of May 2010
True Story -
Cal & Leslie by luv 2 wear cotton panties
«Cal meets leslie at a friends party and asks her out.»
Rated 89.2%, Read 28320 times, Posted Sat 15th of July 2017
Fiction , Anal, Romance, Transsexual -
You'll be surprised by slightlytwistedbitch
«Everybody assumes it was my father or a male relative that got me into the lifestyle»
Rated 63.1%, Read 28320 times, Posted Thu 23rd of July 2020
Fantasy , Bi-sexual, Boy / Boy, Cum Swallowing, Domination/submission, Drug, Incest, Interracial, Male / Older Female, Male Domination, Prostitution, Young -
I own Joyce part 2 Moms Pov by nutzbubby
«joyce gets used and abused & explains why she is a submissive»
Rated 76.7%, Read 28320 times, Posted Thu 23rd of March 2017
Fiction , Cuckold, Incest, Male / Older Female, Mind Control, Water Sports/Pissing -
A happy ending_(0) by lilsweetbaby
Rated 85.9%, Read 28317 times, Posted Fri 13th of November 2009
Fiction , Asian, Blowjob, Consensual Sex, Interracial, Mature, Oral Sex, Romance, Written by women -
All in the family..... my wife n bro by lucky luke
Rated 82.2%, Read 28317 times, Posted Wed 28th of December 2011
Fiction , Cheating, Hardcore, Male Domination, Male/Female, Reluctance, Voyeurism, Wife -
The Royal Genies - Chapter 07 by DragoTime
«Old friends return to my stories.»
Rated 94.1%, Read 28314 times, Posted Thu 25th of February 2016
Fantasy , Alien, Bi-sexual, Consensual Sex, Male / Female Teens, Mind Control, Oral Sex, Teen, Teen Male/Teen Females -
Georgia Part 14 by vanessa.evans
«An 18 yo girl leaves an all girls boarding school and decided to have a fun gap year before going to university.»
Rated 93.9%, Read 28314 times, Posted Sat 10th of March 2018
Fiction , Exhibitionism, Female exhibitionist, Water Sports/Pissing, Written by women, Young -
An Affair Of Different Kind by Nikkie
Rated 65.8%, Read 28311 times, Posted Sat 2nd of October 2004
Fiction , Authoritarian, Cheating -
BUTTERED SALAMI by midniteblueflier
Rated 46.6%, Read 28311 times, Posted Tue 31st of August 2004
Fiction , Anal, Cum Swallowing, Erotica, Interracial -
The Seduction_(0) by Orginswish
Rated 71.8%, Read 28310 times, Posted Wed 22nd of August 2007
Fantasy , Cheating, Consensual Sex, Job/Place-of-work, Male/Female -
tina makes new friends (part two) by Angel
Rated 66.7%, Read 28306 times, Posted Tue 27th of July 2004
Fiction , Domination/submission, Group Sex, Hardcore, Males / Female -
THE WIDOWER by Stephanie Sarg
Rated 77.1%, Read 28305 times, Posted Fri 30th of January 2004
Fiction -
Bicycle tied up_(0) by bager
Rated 78.8%, Read 28305 times, Posted Fri 17th of July 2009
Fantasy , Bondage and restriction -
A chance encounter_(2) by Mega_777
Rated 82.8%, Read 28305 times, Posted Fri 22nd of April 2011
Fantasm , Bondage and restriction, Domination/submission, Erotica, Extreme, Hardcore, Male/Female, Non-consensual sex, Oral Sex, Rape, Reluctance, Romance, Spanking -
Across Eternity: Book 2 - Chapter 4 by Sage_of_the_Forlorn_Path
«Noah discovers a festival of violence.»
Rated 94.3%, Read 28305 times, Posted Tue 19th of January 2021
Fantasy , BDSM, Bondage and restriction, Consensual Sex, Prostitution, Violence -
Margret in Hong Kong by Sarah Lovely
«A young British woman stays at a special hotel in Hong Kong»
Rated 92.1%, Read 28302 times, Posted Mon 30th of July 2018
Fiction , Asian, Consensual Sex, Erotica, Female / Girl, Female/Female, Hardcore, Interracial, Lesbian, Oral Sex, Prostitution, Written by women -
Fuck Thy Neighbor by Londebaaz
«Seth had his both hands on her head, helping her to control the cock sucking activity while moaning.»
Rated 92.1%, Read 28302 times, Posted Thu 29th of April 2021
Fiction , Consensual Sex, Male / Older Female -
Just me and Julia by Cumsthesun
Rated 67.6%, Read 28301 times, Posted Mon 7th of August 2006
True Story , Blowjob, First Time, Male / Female Teens, Romance, School -
Lamars world by master_lamar1982
Rated 31%, Read 28299 times, Posted Sat 3rd of September 2011
Fantasm , Slavery, Teen, Young -
New roommate opens my world by FreshNS08
«My new roommate opens up new fantasies I never knew»
Rated 90%, Read 28299 times, Posted Tue 11th of April 2017
Fiction , BDSM, First Time, Gay -
A unusual situation pt4 V.W.O.M. by justhorny
Rated 86.4%, Read 28295 times, Posted Fri 22nd of September 2006
Fiction , Domination/submission, Female/Female, First Time, Male / Female Teens, Non-consensual sex, Older Male / Female -
claire and abby by reviresco
Rated 93.4%, Read 28293 times, Posted Sat 2nd of January 2010
Fiction , Consensual Sex, First Time, Masturbation, School, Teen Male/Teen Females -
Can't Have it All - Part 2 by megavine7
«Aly starts spending more time with Lindsey, unbeknownst to Elena.»
Rated 94.5%, Read 28293 times, Posted Sat 22nd of June 2024
Fiction , Blowjob, Cheating, Consensual Sex, Cum Swallowing, Domination/submission, Erotica, Incest, Romance, Teen, Teen Male/Teen Female, Young -
THE BEST OF BOTH WORLDS_(1) by Stephanie Sarg
Rated 73%, Read 28293 times, Posted Sat 31st of January 2004
Fiction -
Taking One For The Team 3: Homecoming by SluttySchoolgirl
Rated 92.5%, Read 28293 times, Posted Sat 6th of March 2010
Fiction , Consensual Sex, School, Teen, Teen Male/Teen Female, Written by women, Young -
Harry’s Christmases Part 3 by kj5jx
Rated 84.3%, Read 28290 times, Posted Mon 21st of March 2011
Fantasy , Consensual Sex, Exhibitionism, Male / Female Teens, Romance, Virginity -
Interview With The Tentacle Demon Chapter 9: Anticipation by Perv Otaku
Rated 93.3%, Read 28287 times, Posted Fri 25th of October 2013
Fantasy , Extreme, Monster, Reluctance -
ForceXMass=Domination Chapter 2 The Test by Wet
Rated 68.5%, Read 28286 times, Posted Wed 5th of January 2005
Fiction , Authoritarian, Coercion, Older Male / Female, Young -
Sam 8 by pars001
«A man is taken then returned. He's not the same or is he? Now with a lot of questions he leaves earth to search for the only other one like himself, so far.»
Rated 95%, Read 28284 times, Posted Sat 12th of May 2018
Science-Fiction , Alien, Body modification, Non-Erotic, Violence -
The beach trip part 2 by My Sex life
«Group sex on the beach»
Rated 88.4%, Read 28284 times, Posted Tue 4th of April 2017
True Story , Bi-sexual, Group Sex, Wife -
That Weeknd by lover007
Rated 70.2%, Read 28281 times, Posted Fri 9th of December 2011
True Story , Anal, Blowjob, Consensual Sex, Cum Swallowing, Erotica, Extreme, First Time, Hardcore, Job/Place-of-work, Male/Female, massage, Masturbation, Mature, Oral Sex, Romance, Virginity, Voyeurism, Young -
Hermoines School Adventures - Forbidden fun in the Forbidden forest by Captain Boner
«This takes place in Harry Potter and The Prisoner Of Azkaban just after Harry And hermoine go back in time and rescue buckbeak the hypogrit from being executed with the time turner.»
Rated 56.8%, Read 28278 times, Posted Wed 20th of February 2019
Fiction , Anal, Blowjob, Extreme, Fan fiction, First Time, Male / Female Teens, School -
Brittany and Me part 6 by truebutchanged
Rated 92.3%, Read 28278 times, Posted Fri 17th of April 2015
True Story , BDSM, Bi-sexual, Body modification, Bondage and restriction, Consensual Sex, Discipline, Domination/submission, Female Domination, Hardcore, Latina, Romance, Teen, Teen Male/Teen Female -
My friend's dad 5 by kornslayer
Rated 95.9%, Read 28275 times, Posted Sat 30th of March 2013
Fiction -
Weird Cock Drug Really Made Me Cum Hard by Sorrentino_122
Rated 47.8%, Read 28275 times, Posted Sun 29th of May 2011
Fantasy , Alien, Anal, Drug, Hardcore -
Jen, porno queen by C
Rated 69%, Read 28273 times, Posted Tue 4th of October 2005
Fiction , Anal, Cum Swallowing, Group Sex -
the surprize_(0) by sindy sin
«a big surprize for her birthday»
Rated 89.8%, Read 28272 times, Posted Sun 5th of March 2017
Fantasy -
The harsh new world by jumboowawa
Rated 84.9%, Read 28272 times, Posted Sat 3rd of July 2010
Fiction , Authoritarian, First Time, Incest, Male/Teen Female, Oral Sex, Plumper, Reluctance, Romance, Virginity, Written by women -
Georgia Part 16 by vanessa.evans
«An 18 yo girl leaves an all girls boarding school and decided to have a fun gap year before going to university.»
Rated 95.1%, Read 28272 times, Posted Sat 10th of March 2018
Fiction , Exhibitionism, Female exhibitionist, Spanking, Written by women, Young -
The World - Introduction_(0) by Justin515x
«John finally logins in and joins The World. It is a new full immersion MMORPG game created with no limits. A fantasy based world that is equal parts westworld, RPG, and anarchist where any and all desires can be attained.»
Rated 91%, Read 28269 times, Posted Mon 13th of May 2019
Fiction , Bi-sexual, Domination/submission, Slavery, Young -
How I became a submissive to two masters by dominatemypussy13
Rated 84.9%, Read 28266 times, Posted Sun 8th of September 2013
Diary , BDSM, Bondage and restriction, Domination/submission, Erotica, Exhibitionism, Fisting, Humiliation, Male Domination, Spanking, Toys -
The story of tintin by Johnmi15
«My first experience with a TS, didn't go anything like I expected.»
Rated 92.5%, Read 28263 times, Posted Fri 5th of March 2021
Diary , Asian, Blowjob, Cum Swallowing, First Time, Transsexual -
"Thrice" by julius69
Rated 90%, Read 28263 times, Posted Sat 9th of August 2008
Fiction -
Just As He Is - EPILOGUE by blondeallover
Rated 84.6%, Read 28263 times, Posted Fri 15th of April 2011
Fiction , Anal, Bi-sexual, Erotica, Exhibitionism, Female / Girl, Female/Female, Incest, Lactation, Lesbian, Male/Female, Male/Teen Female, Masturbation, Teen Female/Teen Female, Teen Male/Teen Female -
Creating Voyeurs - part 1 by philh37
Rated 89%, Read 28263 times, Posted Mon 27th of October 2014
Fiction , Exhibitionism, Male / Female Teens, Male / Females, School, Voyeurism -
The first Ride along by neverforget61294
Rated 90.2%, Read 28263 times, Posted Thu 18th of July 2013
True Story , Bi-sexual, Gay, Oral Sex -
Sarah 4 by jmartone
Rated 65.2%, Read 28259 times, Posted Sat 15th of October 2005
True Story , Drug, Lesbian, Threesome -
Simon Says by Seth
Rated 58.2%, Read 28257 times, Posted Fri 16th of September 2005
Fiction , Boy / Boy, Cum Swallowing, Domination/submission, Teen -
Sarah and I_(1) by Psychocock
«Crazy sexual experience with my sister.»
Rated 84.4%, Read 28257 times, Posted Sat 3rd of October 2015
Fantasy , Incest, Males / Female -
When I was a Tutor... Chpt. 1-4 by Khromm
«A young student is asked to help his professors daughter and granddaughter out with some school problems. Turns out, this is not hte only thing he is expected to teach...»
Rated 90.5%, Read 28251 times, Posted Tue 31st of July 2018
Fiction , Blowjob, Consensual Sex, First Time, Male/Teen Female -
Damsel in Distress by Erotic Story Commissions
Rated 62.1%, Read 28248 times, Posted Mon 7th of January 2013
Fantasm , Blackmail, Cruelty, Discipline, Humiliation, Job/Place-of-work, Prostitution, Rape -
Making a Video by IslandGirl
«Girl makes a video, two actually.»
Rated 75%, Read 28248 times, Posted Tue 28th of June 2022
Fiction , Male/Teen Female, Written by women -
The first me and my best friend sucked each others cocks extended edition by Eyez13
«The extended version of my first encounter with a cock»
Rated 85.6%, Read 28242 times, Posted Mon 8th of April 2024
True Story , Bi-sexual, Blowjob, Boy / Boy, Cheating, Cum Swallowing, Drug, First Time, Gay, Interracial, Oral Sex -
Fascination by goodsamantha
Rated 88.6%, Read 28242 times, Posted Fri 21st of August 2009
True Story , Erotica, Masturbation, Teen Female Solo, Written by women -
Daniel Wolf Chapter 18 Part 10 by Wolfen1
«Plans are being made for the war with Torrent»
Rated 94.6%, Read 28239 times, Posted Mon 13th of March 2017
Fantasy , Consensual Sex, Monster -
Sissy Hypno & The Fascinating Return To Porn by Katie_Johnny
«Lifelong closeted sissy gets reintroduced to porn, and discovers her dream of being a sissy has become an entire genre in the porn world»
Rated 93.6%, Read 28236 times, Posted Tue 14th of March 2023
True Story , Blowjob, Cum Swallowing, Drug, Gay, Oral Sex, Transsexual -
Vetriss Academy: The Begining by wordzslinger
Rated 80.4%, Read 28236 times, Posted Thu 20th of May 2010
Fantasm , Bondage and restriction, Incest, Older Female / Males, Rape, School -
My First Boyfriend 8 by Verytas
Rated 91.1%, Read 28233 times, Posted Wed 27th of April 2011
Fiction , Anal, Ass to mouth, Blowjob, Coercion, Domination/submission, Humiliation, Teen Male / Teen Male, Threesome -
My cousin Jo and i, Part 15 by uncledick
«My cousin Jo lene comes to stay for the summer»
Rated 93.7%, Read 28230 times, Posted Mon 9th of November 2015
True Story -
Mom, daughter, nephew: nasty by randomness113
Rated 76.2%, Read 28224 times, Posted Sun 2nd of November 2008
Fantasy -
Adela the Servant Girl by LordExia
Rated 86.7%, Read 28224 times, Posted Mon 10th of January 2011
Fantasy , Non-consensual sex -
harry_potter_01_(1) by Unknown user
Rated 90.4%, Read 28221 times, Posted Fri 13th of September 2013
Fiction , Fan fiction -
School Change by Echoes Valentia
«Boy transfers to a school to find out its more to his liking than he imagined»
Rated 92.6%, Read 28218 times, Posted Tue 21st of September 2021
Fiction , Anal, Female Domination, Male/Female, School, Teen, Transgendered -
A Divorcee’s Unexpected Journey, Part 2 by HornyOldWriter
«Becky's sexual awakening continues as she explores and enjoys the swinging scene.»
Rated 93%, Read 28212 times, Posted Thu 31st of January 2019
Fiction , Consensual Sex, Group Sex, Lesbian, Oral Sex -
Gisele's Story by tw_holt
Rated 88.9%, Read 28212 times, Posted Fri 3rd of July 2015
Fiction , Bi-sexual, Blowjob, Bondage and restriction, Consensual Sex, Female / Girl, Female/Female, Group Sex, Hardcore, Interracial, Job/Place-of-work, Male / Females, Oral Sex, Threesome, Toys -
Breaking the Belt by Dragon_in_bed
Rated 72.6%, Read 28212 times, Posted Sun 18th of May 2008
Fantastic , Male/Teen Female, Teen Female Solo, Teen Female/Teen Female, Voyeurism -
ANNA-BROOKS GETS OWNED, Pt.8 by smokycat67
«Anna-Brooks fascination with an older man leads her farther down the rabbit hole than she ever thought she’d go, as Mike Robert’s introduces her to the BDSM lifestyle»
Rated 93.3%, Read 28209 times, Posted Tue 5th of January 2021
Fiction , Anal, BDSM, Bondage and restriction, Cheating, Consensual Sex, Male/Teen Female, Mind Control, Older Male / Female, Spanking, Torture, Toys -
My Crazy Student_(1) by Wilderness Cry
«My students are off-limits, but that doesn't stop me fantasising about them, and one in particular. If it could happen for real, would I?»
Rated 93.5%, Read 28209 times, Posted Tue 28th of May 2019
Fiction , Blowjob, Consensual Sex, Cum Swallowing, Masturbation, Older Male / Female, Oral Sex -
Harry Potter the King of the Wizarding World by Blake929
Rated 69.3%, Read 28209 times, Posted Thu 4th of August 2011
Fantasy , Fan fiction, Romance -
Vampiric Lust by Jenna_1
Rated 66.5%, Read 28209 times, Posted Mon 18th of October 2004
Fantasm , Death, First Time, Male Male/Teen Female, Romance, Sado-Masochism, Virginity -
1975 – A Year to Remember. Chapter 5 by oldtarheelwriter
Rated 93.7%, Read 28206 times, Posted Thu 18th of December 2008
Fiction , Blowjob, Cum Swallowing, First Time, Group Sex, Male / Females, Oral Sex, Threesome -
my slave Boy -02 by RogueRambler
Rated 76.9%, Read 28203 times, Posted Sun 4th of March 2012
Fantasy , Authoritarian, Discipline, Domination/submission, First Time, Gay, Humiliation, Slavery, Voyeurism -
Best Little Whorehouse on XNXX by ahorsewithnoname
Rated 76.9%, Read 28203 times, Posted Fri 28th of March 2014
Fiction , Anal, Bi-sexual, Consensual Sex, Cum Swallowing, Group Sex, Job/Place-of-work, Oral Sex -
Skipping School_(0) by OhThr33s
«A girl decides to skip school.»
Rated 59.6%, Read 28203 times, Posted Tue 16th of May 2017
Fiction , First Time, Male/Teen Female, School, Teen, Young -
The choice_(1) by Pervertboy1
Rated 67.5%, Read 28200 times, Posted Thu 2nd of October 2014
Fiction , Consensual Sex, Teen, Teen Male/Teen Female, Young -
I Am Not A Shark, But An Orca! by DunafromSOL
Rated 50%, Read 28200 times, Posted Sun 3rd of May 2015
Fiction , Cheating, Lactation, Romance -
Corp Whore by orangegirl
Rated 58.3%, Read 28197 times, Posted Tue 26th of July 2011
Fantasy , Authoritarian, First Time, Incest -
How I Became A Nurse - PART 1 by AVIREXNXX
Rated 80%, Read 28197 times, Posted Wed 12th of March 2014
Fantasm , Blackmail, Blowjob, Boys/Teen Female, Erotica, Female / Girl, Job/Place-of-work, Masturbation, School, Teen -
The Last Witch Chapter 1: The Werewolf’s Prey by GideonBard
«Elara is hunted by a werewolf and must submit to survive»
Rated 83.5%, Read 28197 times, Posted Wed 16th of October 2024
Fantasy , Horror, Male/Female, Monster, Murder -
Hush Money Bar-Part 2_(1) by Schaka
«Todd meets the regulars including Gertrude Allenby»
Rated 91.4%, Read 28194 times, Posted Sun 3rd of April 2016
Fantasm , Anal, Bi-sexual, Black, Blowjob, Cheating, Consensual Sex, Cuckold, Cum Swallowing, Job/Place-of-work, Male / Females, Oral Sex -
The Dream Girl_(1) by youngitunes
Rated 59.7%, Read 28194 times, Posted Sun 25th of September 2011
Fiction , Blowjob, Body modification, Male/Female, Mind Control, Oral Sex, Pregnant, Romance -
Holly's Family Fortunes_(1) by John harris
«Young woman desperate to be accepted into the world of money and privilege nievelly gets used and abused by the people she trusts to make her wishes come true.»
Rated 87.5%, Read 28191 times, Posted Sun 16th of December 2018
Fantasy , Anal, BDSM, Humiliation, Rape -
Journey of a Pain Slut - Act 1 by Sfor
«Have you ever looked across a room and seen someone who you just know will fulfil your every fantasy? A girl perhaps who is trying to hide the marks from her light whipping but is doing so in such a carefree manner that it is obvious she is proud of the welts, and very clear that she wants more?»
Rated 89.4%, Read 28188 times, Posted Tue 31st of March 2020
Fiction , BDSM, Bondage and restriction, Domination/submission, Extreme -
Tourists in Hawaii by hosephm
Rated 73.2%, Read 28188 times, Posted Fri 15th of August 2014
Fantasm , Anal, Asian, Drug, Job/Place-of-work, Non-consensual sex, Rape -
Waterfall Discoveries ( First Gay Time Part 1) by caracol101
Rated 86%, Read 28188 times, Posted Mon 16th of June 2008
True Story , Gay, Interracial, Masturbation, Teen Male/Teen Female -
Trophy Girlfriend Part 5 by vanessa.evans
«A young man slowly introduces his new girlfriend to candualism and she embraces it.»
Rated 95.7%, Read 28185 times, Posted Tue 11th of May 2021
Fiction , Exhibitionism, Female exhibitionist, Written by women -
The Views of May by BashfulScribe
«What starts out as a weekly hike turns into a lot more.»
Rated 89.3%, Read 28185 times, Posted Wed 8th of February 2023
Fiction , Consensual Sex, First Time, Male/Female, Virginity -
Hands-on Tutoring by Krombomich
«A female tutor has to bend to the whims of her annoying student.»
Rated 72%, Read 28185 times, Posted Tue 19th of July 2022
Fiction , Blackmail, Coercion, Oral Sex, Reluctance -
My brother invited me in 2/2 by kornslayer
Rated 95.1%, Read 28185 times, Posted Sat 5th of January 2013
Fiction -
My Old Next-Door Neighbor Nurse. by Speedinator72
«When a young, college guy comes out of a three-year coma, he gets an unexpected surprise from an old neighbor.»
Rated 94.8%, Read 28185 times, Posted Thu 10th of June 2021
Fiction , Blowjob, Consensual Sex, Cum Swallowing, Male / Older Female -
Henry Has Me by ArthurDimmesdale
«Alex is blackmailed into what he has always wanted.»
Rated 89.5%, Read 28182 times, Posted Fri 19th of January 2018
True Story , Anal, Blackmail, Blowjob, Domination/submission, Drug, Gay, Hardcore, Spanking -
highschool, need i say more? by randomjayjay
Rated 87.4%, Read 28182 times, Posted Tue 17th of November 2009
Fantasy , Lesbian, Reluctance, School, Teen Female/Teen Female, Written by women -
Football Coach by SP-20
Rated 92.8%, Read 28179 times, Posted Mon 13th of August 2012
Fiction , Consensual Sex, Male / Females, Romance -
Caught and taught chapter 1 by Roland Deschaine
«A young inexperienced man pays the price for a tricky hotel lock»
Rated 85.2%, Read 28179 times, Posted Fri 6th of May 2016
Fantasm , Black, Blackmail, Domination/submission, Girls domination, Humiliation, Interracial, Male / Females, Masturbation, Oral Sex, Reluctance