Presumably the pizza is left on a counter or table somewhere, and to be honest Lydia isn't all invested in it. She is however, letting her feet bring her nose to nose with Stiles. And if he lets her, she tugs the hem of his scrubs off, so she can his shirt right off of him.

"We are two particularly brilliant people. I don't see any reason why we can't come up with a few options on how to approach this problem."