Man, it was a good thing MC-san's in love with Miku, because going straight to groping and sexual assault without consent is a VERY risky maneuver... oh well, logic checks out in Yuri Land
I just knew someone was going to make a comment like this, and I think in fiction at least it's mostly about reading the room and the right atmosphere. They're both likely going through puberty and horny, combined with how the MC was looking at Miku. Miku knew there was attraction between them and things escalated, so I really don't think this manga has sexual assault in it, but ah well I rather not debate this further than this single comment.