Or get a friend to help....

Normal urine is pretty much free of germs and a good antiseptic -- it's been used for a long, long time as a battlefield wound-wash. When Sir Lostalot had his head bashed in by Sir Furball in the jousts the squires came out and peed on the wound; it got the dirt out and helped kill the nasties that could cause infection.

Mind you, it could be a bit embarrassing if the urine WASN'T "normal". Perhaps your good buddy had the clap and he contributed his bit to the stump of your leg....

Still, sometimes it's better to be pissed on than pissed off.