Done that many times. Last time has to be my worst experience of all time at a football stadium (and use the term stadium loosely). Had a few beers beforehand, and halftime coudn't come any sooner. Rushed to the bogs along with the albion hoards, who had also had a few beers.
It was the time when away fans were behind the goal (We have been in most stands) , to the right side from where the players emerge from the tunnel. The bogs were done in a concrete anderson shelter "styley". Anyway got to the trough, took my hands from my pocket, in into the trough fell my car keys, as gallons of albion piss flowed by.
What would you do? Anyway suffice to say they had no hot water or soap. Never go back. f***ing Matchroom stadium.