well the safest way would be to stand back a few paces and get a nice arc going(think back to when you were young, seeing how far away you could stand and still pee in the urinal). though this method also generates the most collateral damage with the pitter patter of your splashback.
your other option would be the element of surprise. excuse yourself to the bathroom and use what you can to decorate yourself with war paint, start a slow drum rhythm that slowly gets louder and louder. Then come bolting out of there with war cries and the intensity of davey crockett going to rassle a bear.
both methods take some practice but are well proven.