The new way of saying "high five". It serves as a way to say, "hey yo" to friends, but includes rules. The rules: 1) When left hangin it is a "fumble", so anyone can steal it (after the person left hangin screams, "FUMBLE!"). 2) If you feel like being an asshole, or just feel like bringin some big defense into it, you can get an "interception" by basically putting your hand in the middle of some slappy happy that is goin on and stealing the slap from someone. The best defense is a combo move that takes electric hand speed; it could called both the “double interception” or “interception-fumble” because you hit both hands that are going for some slappy happy in less than 2 seconds. Slappy happy is extremely popular in high schools and colleges in both urban and suburban areas. Slappy happy is sweeping the world, and has been used on televsion in a Dunkin Donuts commercial. Slappy happy was birthed by Nick B. in Wilmington, Massachusetts during his sophomore year @ Wilmington High (Class of '07).
Nick: Hey son, gimme some slappy happy.
*Nick proceeds to collide hands with a friend, which almost always makes a painfully loud slap sound*
Friend: Ok yo, I'll see you around later.