You hesitate (alt)

"I...don't know if I should..." you say lamely. Your cock grows from half-mast to fully hard. Kayla thrusts her tits out to you a little more.

"Why so shy?" Kayla asks, "You weren't shy this morning" referencing you using her mouth to get off.

Eve's doing her makeup when she says, "Yeah, what is the big deal? Just be a friend, John, and see if the makeup comes off her breasts when you play with them." Your eyes bulge from their sockets and your dick twitches in your pants, as if trying to escape into the cleavage. Did your girlfriend just give you the green light to feel up her friend? You cautiously reach out to grab Kayla's boobs, your eyes watching Eve's through the mirror, but she only glances and smiles at you, before focusing back on her makeup.

You squeeze and play with them a little bit, before she pulls away and says, "Alright let me see your hands." You show them to her - no make-up came off. "See Eve I was right!" Kayla says smugly. She turns away but you grab her arm.

"Yeah but you know guys are going to do much more, right? Probably need a more thorough test," your dick is running the show now and you press your luck. Eve even chimes in her agreement!

Starting to undue your pants, thinking of fucking those massive tits, your girlfriend yells back at you "What the fuck, man!" Kayla isn't going to be getting tit fucked by random strangers. "Oh, ..." you think blushing.

Kayla smiles at you and shakes her head, "Men..." she sighs, breaking the tension and takes position in front of you again, and you start biting one nipple hard enough for her to flinch, pinch the other one roughly with your free hand. After 30 seconds you switch. Your cock is painfully hard at this point. She eventually says, "Uh ok, I think that's probably good enough..."

You pull away and look in the mirror, seeing no makeup. Kayla sees this too and is satisfied. She turns away from you again intent on finishing her makeup.