MC visiting the bathroom, and can encounter the goblin there.. the MC chooses the route to take.. or anal, etc. Being the one to *choose" means they're in "control," no? With the "training" the MC gets, the choices given are to top or bottom.. again, putting the MC in control.
I had expected you to have actually *played* the game enough to realize. So didn't think I needed to expand further. My bad.