10 - 15 at a time, during regular Circle Jerks, when I was at school, but only about 5, tops, in my adult life, after losing at Strip Poker, or some such game, where the losers had to masturbate in front of the others - although the question remains, who were the real losers / winners?
should have made the screen name Pornst*r. anyway the only person i know that has seen me was the person who showed me what it was.
10 of us, my entire junior high basketball team at a sleepover at my house. After lights out, it was a team circle jerk.