As for the whole "Rin acting like a guy", I don't see it. The only way that would make sense is if you assume girls don't get eager, even pushy, about sex. Which I assure you, actually does happen.
Calling it "rape" or even close is equally overwrought. I mean seriously, we hear directly from Maki several times that she likes it, and that she enjoys what Rin does. She just thinks Rin has too much stamina and is playing the stereotypical tsundere in that direction. Not to mention, I think Maki underestimates just how hard she's fallen, and indeed is still falling, for Rin.