When it comes to accepting the dare of a Marine, one has to think long and hard about the consequences, should you lose. Carl is willing to take the risk, in this case.

(Anything she did to him, he'd probably enjoy.)

So with one hand against her back, he brings the other up to the back of her neck, and he pulls her closer for a kiss. If she lets him, she'll be rewarded -- apparently sugar intake makes him feisty -- without delay.