A buddy of mine will always tap the cap of his snapple bottle with his index finger (tap tap tap) before opening it. I don’t think there is any benefit to this. I have never asked him why he does it, thinking that it’s a personal thing and I shouldn’t get involved. Anyone else have or use certain gestures which can only be perceived to have a hidden meaning?
Snapple tapping may be a bastard child of soda can tapping. It is believed that tapping the soda can before opening it will keep it from fizzing over. I’ve done it since junior high and will probably keep on doing it. I’ve heard the practice derided here on the SDMB, but that won’t stop me. I remember many a time in junior high when someone shook up a can furiously, and someone tapped it, and it opened without a fizzing eruption. I think I’ve heard there’s a new design to cans that keeps them from fizzing over, but I seem to remember many other times in those days when sodas did fizz over, so it seemed to make a difference.