I've been caught beating one a few times, but it would take something rather drastic for me to actually stop tugging. Usually it's a look over the shoulder... 'Shit, I've been caught...' and then a rather furious hustle to get that spunk slug out so I can concentrate on the next one. If they're still stood there by the time I start the second dance then they're the one with the illness, not me. As for sex, my girlfriend's foster sister sat and watched us lose our virginities to each other.