I think this relationship is ia actually messed up seme only have urge to sex only when uke crossdress and uke accepted it easily cuz he is self cautious guy it's not that good. When seme is unsure of it's feeling it always bugs me especially when they are popular.
The sister is the real mvp. She is the most mature and full of senses in this comic. And thanks for her, mc and ml slowly trying to understand what the healthy relationship is. still uke need to build more confident. Need extra chapter to know they are official dating.