I respect a hearty urinal fart. You need to both lack shame and teem with confidence. Here is where "I don't mind s**tting air in front of a colleague," weds an absolute faith that not a toenail will cross the gas/solid line.
I was just in the men's room, and a mid-50s gentleman blew through three farts while taking a leak. I left the sink running for him, in case he needed to launder his briefs.