<human>: So this is actually my friends fuck up that I was in the bathroom to witness a few years ago. We are in the bathroom of a gas station, which has one urinal and one stall next to it.  my friend walks in first into this empty bathroom with me following and proceeds to the urinal.  what he didn't see, was me holding the door for an older, well dressed gentle man, who slipped through the door as my friend was approaching the urinal.  I proceed to take the stall.  

 
  
halfway through the pee, my friend lets out a huge, ground-shaking rip of a fart that seems to last 3-4 seconds. As the stall was still rattling, he loudly groans in his most deep, guttural voice, 'THAT SHIT WAS DEEEEEEEEEEEEEP!.'  I try to control my chuckling, holding my breath and such, as I realize that my friend has no idea that there is an stranger standing right behind him.  but upon opening the stall, I couldn't control it.  the man just stared past his perfectly shiny leather vest down at his matching leather boots, his clean cowboy hat shaking in rhythm this his head.  My friend didn't wash his hands.

Summarize the given text in a few sentences.
<bot>: My friend let out a fart at a urinal without knowing a stranger was behind him, then further embarrassed himself with his own commentary.