TOMT late 2000’s early 2010 black comedy movie

I remember watching this as a kid but it was definitely not child appropriate.

I only remember a few scenes the first one the main guy gets pants and hes more a like a nerd type , everyone sees his dick and makes fun of him and he goes to the principal (?) who give him advice on how to remove lint or something from his penis.

Theres a scene where the song just my imagination by the temptations plays as the love interest walks by but it gets interrupted by either her rejecting him or him being splashed by water (the end bit if fuzzy the main part is the song)

last theres a party scene where they are playing 7 minutes in heaven and when they go in the closet they show on camera the guy rubbing the girls ass and then it fades into another scene.

I remember having this on DVD but i cant remember the name :((( , any help is appreciated!