That comment probably has the opposite effect that Steve wanted. Natasha starts to giggle, a mixture of nervous tension and the the fact he's not even remotely kidding about it being a long time forcing a fit of laughter out of her.

"Uh...sorry." She pulls back and look him over. Tasha doesn't want to explain. There's a good chance she can't explain. "Sorry. Where were we?" She smiles before leaning in to kiss him again.