"Email ping-pong" is the act of email correspondence between two people getting out of hand or control.

It usually starts of with a comment, opinion or observation that becomes misunderstood or misinterpreted by the recipient. The recipient then responds with comment, opinion or observation...and so on. It is not uncommon for participants to ping-pong 10, 20 times or more before they realise they haven't got a clue what started it all in the first place!

A game best played when your opponent is drunk and very attractive.

Sex partners...

Either classic Table Tennis played in the nude, or the same game played like Strip Poker. Each time a player loses a match, they lose a piece of clothing. It is advisable for female participants to choose to keep their bras rather than their panties, as free boobs can severely impediment the game.

Generally played socially rather than competitively.

Small, perfectly round and not saggy breast.

A game where one plays table tennis and the loser must remove a layer of clothing.

An otherwise normal game of ping pong, except that everytime one looses a rally, the individual must remove an item of clothing whether it be an entire sweater or a small sock.
It is up to the players to determine whether jewelry counts.