I say this song is about that very, very anticipated date. The one when you KNOW you will have sex (which they do) Wether it´s an easy girl, or a girl you´ve dated a couple of times before, but this is THE date. You KNOW you´re getting laid. So the anticipation is so big, that only a kiss will give you the "It´s starting!!!!! This is it!!!" feeling, at that very second, as a guy, you lose is. You´d do anything to go on, you´d give your heart, your car or your house to that girl. My guess is the girl is maybe more experienced than he is, which is why he says "you kissed me like you meant it!", like, she´s done it before, she´s slept with guys before, she could´ve chosen to sleep with any other guy. She chose him, and he feels like there´s a reason for that, he feels like he´s important and that day, and that day matter, because he matters to her for that day, at least. So it´s pretty much just about where you get laid, and you feel great.