She freezes up.

Sophia's hand freezes as she hears Diana's words. You inwardly curse your luck. Diana took things too far by suggesting Sophia put you in her mouth.

"Umm," Sophia says, "I'd feel a little embarrassed to do that. It seems a little, I don't know, weird?"

Diana nods, "I totally understand if you're embarrassed, and you certainly don't have to. I will say that it's not weird at all though. A lot of people use saliva to lubricate, and using your mouth to pleasure someone is actually a very common practice."

Sophia nods as she moves her hand off of your cock. "Well, maybe...you could demonstrate? I don't think I'm brave enough to try it."

Diana looks down at your hard penis, and up at your face, which is probably showing your disappointment at no longer being touched. She hesitates.

"Oh, well, I understand why you'd ask that, but Joe and I are friends. It might be kind of awkward for him, for both of us, if I were to do something quite so intimate."

She looks questioningly at you; she seems to be curious about your reaction.