Unusual Kissing

Listen up, smarty-pants. This joke is funny because it sets you up to think about a normal kissing situation, but then it hits you with the "not regular kissing" part. Like, what kinda kissing were they doing? Were they using tongue? Were they upside down? My point is, I bet you thought about that. And since you are probably still in middle school, you probably blushed a little bit. I bet you're even holding your breath right now because you're so nervous.