Im lookin for this one manga i read a while back. It was Adult/Mature borderline Hentai (but not). It's about a plain guy(i think) who one day witnesses the school idol masturbating in class. Soon they have this "relationship" where she's always giving him a BJ. In one chapter some other guy ties up the protagonist and beats him i think but the girl stops him and ties him up instead and gives the protagonist a BJ in front of the bully to show him that shes not all princess-like that he thinks.

Henkoi! unless I am mistaken.

yes. thank you. it was really bugging me trying to find it. thankx again