Easiest solution would be to hold him for less than five minutes?
Nervous snakes pee. My YB was a big pee-er when I first got him, it passed soon enough.
Also keep in mind if he is being handled he is more likely to urinate or defecate from the pressure, etc. You can squeeze urates, urine and feces out of snake without too much trouble.
Could it be HOW he is being handled, vs. THAT he is being handled?
Bruce