What does this upside-down OK gesture mean? Here it is on a t-shirt:
As the name states, it’s the “punching game” symbol, played by schoolyard boys. Basically you make that gesture down around your waist, below eye level, and if you catch someone looking at it, you punch them.
Sophisticated.
Yep, the “circle game”.
My friends and I used to do that in the mid-sixties. The rule was the sign had to be touching some part of your body (leg usually) below the waist. We were all wise to the game and so the challenge was to try to come up with a plausible and innocent-seeming way to trick someone into looking down, whereupon they became punchmeat if they did. Most of the time days went by before someone tried it because if you did it all the time nobody would ever look down.
Ahh…good times. 
P.S. - The punch was usually delivered with a balled fist with the middle-finger knuckkle protruding, which mean that most of the force was being transferred through that roughly half square inch of knuckkle and it a was pretty painful jab. But, ya had to sit there and let 'em do it, or you were a wuss and lost cred with your buddies.
And two for flinching.
I remember this game from elementary school, and it made a comeback in high school.
In Brazil and a few other countries it also has something to do with calling someone homosexual.
http://westsidetoastmasters.com/resources/book_of_body_language/chap5.html
We also had a rule that if you could “plug” the ring with your finger, you got to punch the guy making the ring.
Holy Crap! I hadn’t thought about the punching game in 30 years.
Heh. I once made the sign on my knee when I was kneeling in the front row of a team picture. When the picture showed up in the newspaper, I asked all my friends if they’d seen it. POW!
Looking at that picture, it apparently means “I’m gay and a bottom”. YMMV.
Never played the punching game. So glad I was a social misfit.
So what the hell does a floppy disk have to do with “blow me”?
It’s a Nintendo game cartridge. As many children of the '70s and '80s will tell you, blowing air onto the cartridge connectors was the way you attempted to fix any problem with the system - blinking red light, green screen of death…
As it could blow out any dust that had accumulated.
What part of “schoolyard boys” suggested it was going to be otherwise?
