Oh, it's quite easy. My cousin is one of those dumb asses who can't put the straw down for a week, so in the past, I stupidly agreed to supply him with a sample. He'd just put it in his boxer briefs and take it out when needed. They don't pat you down or anything like that.
Now that I've told him I'm not going to help him (enable), he gets it from the net. Yes, they sell clean urine over the internet.
Damn. I guess you really CAN get anything online.