A series of self given high fives driven by one of the following purposes:
1. Congratulate someone else's achievement.
2. Acknowledge the end of a joke, speach or musical scene.
3. Sing the "Happy Birthday" song.
4. Force the speaker to shut the hell up.
5. Kill a flying insect.
6. Mimic a seal.
7. For the sake of peer pressure.
You see, the applause is only present in the Happy Birthday song to prevent us from realizing how ridiculous it is. Try to do either of them separately and you'll get what I'm saying.
I'm just starting the applause so everyone can tell the joke is over and it's ok to laugh.