Yeah, when your asking "why won't she have sex with me?" You've sailed clear past Class-S conventions. The use of "straight" here is so bizarre. Maybe it's a translation thing where there's only terms for "lesbian" and for "everyone else"? It wouldn't be surprising if the terminology centered men and how available women are to them.
That's what I figured, or at least some degree of "Never been with a woman before" like, bicurious or w/e. Also playing off the phrase straight as in she's pretty nroaml too.
That said, god this is good as hell, and I'm excited to see more. The senpai's fucking hilarious