I personly would not ask anyone to do that, just becuase you cannot tell now a days what someone has before you deside to injest bodyly fluids.

I also, IMHO question the merit of a Dom that in this day and age would task you with something so dangerous. For all you and your Dom knew, the first person to walk in that stall could have been compleatly homophobic and might have hurt or killed you for trying to do something like that to them. I personly think you are lucky to be ok.

Again, i do not mean to to insult anyone with this post, i am just giving my opinion.