@plex_is_better is right. The quote is from a show called 'The Office'. And you're actually wrong @jonconnor - there are a great many injuries/conditions that can be relieved by urine. Someone suffering from hypothermia can benefit greatly from being urinated on. Also, because urine is sterile, it can (and should) be used to clean open lacerations in the absence of clean water (eg: if you're hiking in the bush and get a bad cut and don't want to waste precious clean drinking water to clean it out - PEE ON IT!). There is also some evidence that peeing on a sunburn can reduce pain and promote healing.

It's a quote from a comedy TV show. It's not supposed to make sense. It's supposed to be dumb.

Why are you being so weird, you don't pee on your own leg. STOP being dumb