Especially if they bullied him before.
Stuff like:
Baka Dakedo (Guy tutors his slutty classmate in exchange for sex)
Hajimete no Hitozuma 4 (Guy loses his virginity to the school slut)
Otaku no Yasashii (Same as above)
Jk Genkai Koubi (Same as above)
Energy Kyouka (Same as above)
JK Bitch no Shiboretai (Otaku has sex with all the sluttiest girls in his school)