Honey, there isn't a joint in my body that is so. There's definitely utility there. Anything interesting you can do as a result of being double-jointed? I can make my arms work like a jump-rope. Auto-fellatio is also a nifty plus.
I can move my left and right eyebrows independently of each other. I can wiggle my ears. I can make a fairly loud popping sound by sucking my lower lip down from my upper teeth and upper lip (I started doing this as a child and assumed that everybody could do it; I was surprised that most people could not even figure out what I was doing, much less do the same). I can curl my tongue (sides toward center), but I have never been able to do that really loud whistle that some people can do.
I can do that with my arms too - it totally freaks people out. I haven't really found a great deal of use for it other than sexually. And again, some people have thought it was the best thing ever and some just got weirded out.
Sometimes I can shoot full load of cum without orgasm, still trying to learn how to control it. When it happens I can jerk off, shoot full load and keep jerking off like nothing happened. Wish to take video of such session!
Ben wa balls and golf balls. The golf balls are around my size comfort limit it's hard to force something larger and rounder past that tight ring of muscles we were talking about in the other thread. The larger it gets the harder it gets to get out much less shoot out with any kind of force. The bigger stuff is more of a pop suddenly and I can control the muscles to do it slowly with larger objects like plastic easter eggs and kind of have them hang there:tongue: The Ben wa's I can send the furthest. I learned it by accident, then I became preoccupied with seeing how far I could send things:redface: