Man, just the visual image of sounding freaks me out.

This has always been a hard limit for me, though I have never tried it and therefore am admittedly ignorant to what it's like. Before this thread I thought that sounding was supposed to be extremely painful, I didn't know that it's just a little painful but somewhat pleasurable. Even knowing that though, I think this is one of the few things I can safely say will never leave my hard limits list, if only because visualizing it alone is enough to make me feel faint!