Imagine Aizawa getting off to Allmight pretending to be a villain and Toshi just rolling with it. Maybe it sort of slipped out when Shouta was getting dicked down nice and steady when he wanted it hard and mean? A little roleplay never hurt nobody and Aizawa must look mighty delicious when desperate and forced to comply (you can’t tell me Shouta didn’t fantasize about the scenario once or twice while fighting all those bad guys of the week)