(A/N: i really don't know why i made Y/N a Masochist but it is what it is)
(Lemon Warning!)
Y/N had a secret a humiliating secret he was secretly a masochist he didn't know why he take pleasure from being hurt. He didn't know what to do so he joined the service club and told the members about his Masochism. He asked the members how to fix this but Hachiman and Yukino didn't know what to do. So Y/N just stayed in the club because it was "Fun" to help other.
Then One day. The door suddenly flew open and came in a Woman wearing a white coat.
Yakino: Ms. Hiratsuka please knock before you come in.
Hiratsuka: Yeah yeah so who is this g-
She stopped mid-sentence when she spots Y/N she just stood there staring at him with a blush.
Yuigahama: Uhmm Ms. Hiratsuka are you ok?
Hiratsuka: ...
Hachiman: Ms. Hiratsuka?
Hiratsuka: ...
Yukino: Ms. Hiratsuka!
Hiratsuka: Uhmm y-yeah?
Yuigahama: Anyway this is the new member his name is Y/N and he's a Masochist
(Y/N): Hello there Ms. Hiratsuka :)
Hiratsuka: Hello. So Y/N you're a Masochist?
(Y/N): I'm ashamed to admit it buy yes I am a Masochist.
Hiratsuka: Don't be ashame there nothing wrong in being a Masochist. Tell you what I'm actually a sadist so we don't have to be ashamed ok :)
(Y/N): Y-yes Ma'am :)
Hiratsuka's Mind: So this boy is an Masochist i knew it that's why i felt a connection when i first saw him. We're basically perfect for each other. And he's smile oh it's so cute and bright i want it only to myself. I want him only to myself No one else. I'll have you no matter what Y/N and we'll be together forever
Yakino: So is that all Ms. Hiratsuka? We still have matter to attend to.
Hiratsuka: Uhm Y-yeah just stop bye to say hi that's all.
Hiratsuka then left and made plans on how to get her beloved Y/N. Then a plan formed in her head and she smirked gleefully.
Few days later Y/N was just minding his own business while inside the bathroom.
While washing he's hand suddenly a cloth was put into his face he struggled a bit. But he soon was on the floor unconscious
Unbeknownst to him it was actually Hiratsuka who attacked him. Hiratsuka carried the unconscious Y/N to her car and drove home. Where she put Y/N in her basement with a bed and a table.
After an hour or two Y/N finally wake up. He was scared and confused because he didn't know where he is.
Then from out oft he shadows a woman came out. Y/N didn't recognize her face because she was wearing a hat, a mask and sunglasses.
Y/N's captor walked towards a cabinet and took out a bag full of BDSM tools. Y/N gulped because he knows if he will get tortured instead of pain he'll be pleasured.
His captor took out a whip and walked towards Y/N. Y/N tried struggling but because of the restraints he can't do anything.
Y/N was whipped 20 times and everytime he would moan out loud. The captor then took out a different tool and used it to him and he would take pleasure in this tools.
(Y/N): P-please no more I'm at my limit please stop.
???: Stop? Darling we're just getting started.
The captor then took out her panties and a pad and revealed her Large dick. She was a Futanari.
(Y/N): Don't! Please don't!
The captor didn't listen abd positioned her dick into Y/N's ass.
(Y/N): No don't! Stop! I won't fi-.
Before Y/N could finish his sentence the captor thrusted her dick into his ass. Y/N instantly came when the dick went into his ass.
The captor then fasten her thrusting into Y/N's ass. Then the captor removed her disguise Y/N was shocked that it was Shizuka Hiratsuka.
(Y/N): Hiratsuka-sensei! Please *moan* stop this! *moan*
Hiratsuka: Oh honey just call me Shizuka or Honey. And stop this why would i? Your actually enjoying this you Masochistic slut.
(Y/N): W-what *moan* are you saying *moan*
Shizuka: That's what I'm saying your moaning and it's sounds like you like it.
After a few minutes of them having sex.
Shizuka: Ohh i Cumming Y/N! I'm gonna shot it inside you now.
(Y/N): No! Don- eeek
Shizuka came inside Y/N. Y/N thought it was over but then suddenly not even a minute has passed Shizuka thrusted her dick into Y/N's ass again.
The ordeal lasted for 2 hours and 5 rounds of sex. And in the end Y/N mind has been broken he can't think of anything but Shizuka's dick.
After that Y/N dropped out of School and Became Shizuka's Husband well more like sex-slave.
The end
(A/N: I think shizuka didn't had many aspects on being a yandere this story is like she was only Semi-yandere. Sorry if story sucks i had a writers block)