Mm-- [That hurt. But he holds back any sign of protest in favor of experiencing Kaworu's orgasm in full, enjoying how hard it shoots and explodes inside him, making him feel warm and dirty and all those things any good fight can bring him. Only this isn't a fight, and Kaworu isn't an opponent, but because Axel's just a natural born assassin he translates everything into violent terms anyway. He doesn't have sex to be romantic or to create stronger bonds--at least that's what he tells himself--but rather to sedate his curiosity if only for a few short moments post-climax. This is what humans do to feel good and this is what humans do to learn and advance...so why shouldn't he?
So with eyes full of deep intention and concentration, he locks onto Kaworu's face as he milks him for everything he's worth before he too finishes, fingers tightening around the base of his cock as long strips of fluid squirt out of his slit, staining not only his abdomen but chest as well. And he makes little noise when it happens, too, if only because he wants a bit of his dignity to remain intact. So Axel simply rolls his head to the side and falls extremely limp onto the bed...just a sweating mess.