This is one this artist's hotter comics, and it thankfully doesn't contain mindbreak/sex slavery (unlike that one about Yukari). 21 definitely made me chuckle, because the guy appears to be trying to persuade Futo to do his fetishes, which there appears to be a Japanese-girl's gym uniform.
I'm going to call it: Page 13 looks like mild defloration. Notice how the juice around the mating point looks darker than the rest of it? It could be just the way it was drawn in that spot, but increasing the validity of my claim is that he just fully penetrated her.
Base +23, rjulios234 +7, Kona-chan +9, hondawhr +24