Someone (can be an OC or a character we know, whichever works best) dares Matt and Foggy to kiss at a party as a joke/prank/game/whatever, because everyone's always teasing them that they're practically a couple already. Of course, said outsider suddenly starts getting uncomfortable when they realize that Matt and Foggy are...getting really into it. And suddenly it's hot and intimate yet somehow also personal and sweet and they feel like they're interrupting a private moment and IT'S BEEN GOING ON FOR AT LEAST A MINUTE AND A HALF AND THIS WAS SUPPOSED TO BE A QUICK PECK. And they're just going to go now because those two are finally breaking away and judging by the looks on their faces Matt and Foggy were about as surprised by that as the original dare-giver was...

(It's their first kiss, just to be clear. Double triple quadruple bonus points for describing the kiss in really lush detail.)