Someone did that bottle knock thing to me once at a bar, where they thunk the bottom of their bottle onto the top of yours. I have been waiting over a decade for that to happen again so I can put my thumb over the top and see if I can make it spray like a hose at whoever does it.

I think at this point I have to accept the fact that I no longer hang around that kind of immature crowd, and if I wanna test it, I'm going to have to run an experiment in a controlled environment. (read: buy two beers and do it myself.)