I have a memory of it being the tip of the middle finger circled in front of the crotch in a motion similar to clitoral masturbation, but there are also a whole pile of variants/dialects of sign.

Sign language can be fun. There’s a great Adam Hills special with a sign interpreter where he says, ‘there will be a lot of moments tonight where there will be a laugh as I deliver a punchline, and then there will be a second laugh a moment later as everyone sees the sign for clitoris.’

DM: *snaps fingers* Done. Calm down, Tom. I’m not going to punish you for being creative. You can get creative as much as you like. Hell, thats the point. …BUT, just remember, you will never, and I mean NEVER, win. There is no magic combo that lets you ‘win’ an RPG. You keep going or you don’t. There is no ‘win’ state. For now, they fire the test shot and demolish the tree at which they fired it, plus some others in the ricochet path. They both get an adrenaline rush as they realise how dangerous this could be. Now, what do the rest of the group do with their day?

I’m not familiar with every one of them but the ones I am familiar with sound mostly wrong, so I expect the others are too. Seems mostly to be belittling people to make the author feel special. I don’t like it, and the comm would not be worsened by its deletion.