Test them further

"I'm going to have to do some more tests." You tell the girls as you approach Black Widow from behind. You spread her cheeks and slide your hard cock into her asshole. She moans a little. It's very tight. You thrust in and out a few times reaching around to play with her tits.. "Do me! Do me! Mine's tighter!" Mary-Jane yells, still in position. You slip out of Natasha's ass and she looks back over her shoulder in vague disappointment.
"Come back soon." She winks. You move over to Mary-Jane who sticks her ass out even further for you as she leans against the wall. You slide in. It's not quite as tight Natasha's, she's clearly more used to having her asshole used. You move in and out gently. "Harder! I can take it!" She encourages as she slaps her own ass. You thrust harder and harder, testing her limits. Black Widow moves off the wall to watch you pound Spider-Man's wife. She moves over and uses one hand to play with Mary-Jane's tits and the other to help you spread her cheeks, spanking her occasionally. "Cum in my ass!" Shouts the redhead as you slam her against the wall. You feel yourself ready to cum.