So....

Black hair dude has OCD due to him being raped by his father since a certain age, blond dude's liked him for a while so he confessed knowing that they won't be able to touch. But he had hope that someday they'd be able to touch as seen in the start "I would die with you but i don't wanna die before having sex with you". Black haired dude is obviously suicidal, so his response to the blond was "You can have sex with me after i die". Black haired dude kills his father during getting raped because he's fed up with the constant abuse, blond who got his call went to their house and found out for the first time that black hair's condition was because of the abuse and wacked the dead father's body with a bat. They ran out there and black haired says that he can't live with the aftereffect of this event, he kisses the blond for the last time and slits his own throat. Blond carries him back into his house and participates in necrophilia by having sex with the dead black haired dude's body, which was something he consented to when he was alive. Anyways the end insinuates him slitting his throat and joining the black hair dude lol ze end