(some play so you only drop your trousers and underwear, or for girls, take your top and bra off)
see also six balled and five balled
"oh man, he seven balled me yesterday, everyone saw my cock"
"lol you got pwnt"
Other guy: HAHA! Take the clothes off.
The next day:
Guy to friend: I was seven balled last night. The other guys saw my cock.
Friend: Oh god!