If this happened to be a show, I’d assume the premise would go like this:
Virgin and Chad are on good terms with each other, but not exactly buddy-buddy. Virgin harbors jealousy towards Chad and the fact that he can do almost everything better than him, while Chad looks down on Virgin for being so weak and disregarding exercise as a whole.
On the other hand, Normal-chan and Other-Girls-Sempai (or OG-sempai, as I’ll call her) hate each other’s guts. In fact, Normal-chan is fairly misanthropic and will criticize anyone she sees for literally anything. The only person she seems to like being around is Virgin, them being childhood friends.
OG-sempai and Chad are dating, her being his 326th date.
Virgin has a crush on Normal-chan, but just can’t seem to spit it out; subsequently, he seeks Chad’s help since he’s dated multiple women before and has a lot of experience when it comes to dating. Chad agrees to play the role of the cupid for him.
Obviously, OG-sempai isn’t happy about this. Not only is Normal-chan starting to enjoy herself, but Chad is too busy hooking the two up that he pays less and less attention to her. In order to stop this, she tries to sabotage as many of Normal-chan and Virgin’s activities as possible.
tl;dr Virgin has a crush on Normal-chan, and Chad helps the two become lovers. OG-sempai doesn’t like this and tries to split the two apart.

I wish I looked half as cool as the virgin.