Satoru was highly against of the idea of his friends dating you. He didn't like it because he knows what type of guys his friends are. They literally have a fraternity together and party every weekend. So logically it makes sense that he doesn't want his sister breathing the same air as these men or even spit.
But that's not enough to stop suguru, oh no you drive suguru up a wall with your beautiful eyes and your dazzling smile. Nothing really discourages him when it comes to women. He knows he's a pretty boy and has good game, until you genuinely reject him not because he's not hot. But because you think he's a loser.
Technically he's not is what he tells himself.... But sleeping around and not getting good grades doesn't necessarily scream good boyfriend material. Then Satorus constant nagging about staying ten feet away from his sister or he'll kill him even if they've been best friends since forever.
During boys night at your house you come down after Satoru calls you for dinner. Grabbing a piece of pizza and bitting into it you don't notice you got sauce on your face. Suguru goes into the kitchen to grab a drink and looks at you and chuckles.
He wipes your face and smiles "Messy eater are we princess?" He then walks over to the fridge and opens it "Beer or soda? Maybe juice?" He turns back to look at you