Well they could go up the adulthood ladder as well buuuut that would make this beta virgin MC become alphaish or so and well, that's not what the story is about anyways since plot demands that he has to keep being a selfcucking virgin beta MC until the end (I mean the story finishes and they never did it).
But also doing it in this kind of situation could bring him trouble with yame since it would look like he has been thinking of doing it all the time and that could potentially make yame not have very favorable opinions of him. So yes. The proper course of action is SLEEP or spend the night talking about whatever (LIKE A BADASS GENTLEMAN🧔👊), unless it yame herself the one that initiates it THEN he can go all the way with her LIKE A BADASS BAD BOY😎🤘 (even though we all know instead of him wearing male clothes he should start asking trap boy about what kind of female clothing and underwear he should use since he is turning into a girl from all the selfcuks he does to himself and all the times he has shown that he has a pussy instead of a D).