a group of children (2-10) children gather around in a circle around a flat surface (table, desk etc.)
the first person places there hand on the table the second player slaps the first players hand as hard as desired and then the third player and so on. until the first person may use their second hand to smack the previous players first hand. the cycle repeats till each player has used both hands.
repeat the cycle, by removing the bottom hand of the first player and smacking the hand of the person that struck their second hand and so on. so that eventually every player will be at the bottom, then remove their hand and smack again.