Soil stuck in tortoises.... "intimates"

[Rambotron]

Hi All,

My tortoise, Irwin , has reached maturity recently and sometimes displays himself (when urinating or for 'fun') the only issue is, I keep him on a mix of coco coir and loam and he ends up with substrate stuck on his bits

I assume this happens in the wild so I wouldn't be too worried except it seems to be uncomfortable for him and he spends a long time afterwards shaking his tail around and straining.

I dont want the force of him straining to shake off substrate to cause him a prolapse or anything.

Does anyone have any suggestions?

Hes a 5-6 years old Mediterranean Spur Thigh, I adopted him 3 years ago.
I thought he was a female at first but the vet set me straight a while back. Hes not tried to hump anything yet lol, its like hes just discovered his junk and isnt too sure what to do with it.

As a bit of background, not long after I got him he passed an enormous urate mass that had been building since before i got him. He was treated by the vets for a while after to ensure no further build up but he tore his cloaca during the process of passing the stone and although healed no, it remains somewhat 'loose' and so soil enters easily.