All require you to have 15 relationship from recess stuff.
Jason:
go to his house and hang out a few times. his dad tries to get with you. tell jason and follow the quest from there. in the end he'll give you the option: fuck him or fuck his mom. Choose the latter. after a small quest at the church on the weekend, you can hang out with jason in the afternoon and then the room will go dark and you can go to the mom in the living room. Make sure you have wine in your inventory. It will take some grinding before anything happens.
Charles:
After playing Pokemon go at recess you talk to him in the schoolyard during the afternoon next to pam. He'll tell you he's a virgin. so you can either set him up with jet or markus's apartment there is a prostitute for 300 bucks. I chose the whore. He lasts two seconds then you jump in for an interactive session. afterwards he tells you he hates his sister and wants you to destroy her with your dick. But you have to be popular on youtube. make videos from here. The fastest way to raise popularity is to do videos on trending games.
Phil:
after collecting bugs brenda quest style, you can hang out a bit till one day the room goes dark and you can talk to his mom. The hint is that if you dont visit for a while she will worry. I don't know how long that is, I'm still waiting.
I'm guessing that if you saw Rachel in front of Jason's house and the sex scene too monday morning go to school and BEFORE entering your classroom talk to Jason and he'll give you another quest.
For Phil if you have a 15 points relationship with him after school go to talk to him(he's near Ms.Taylor)and he'll give you his quest.
For Charles i didn't started yet so i can't tell you what to do.