BLUE TONGUE SKINKS

I posted this as a reply on my previous post but as it's unrelated I thought I'd post a separate question...
I have a query about substrate, my skink is currently on shaved aspen (which I intend to change) but I've noticed when he goes to the toilet his man parts pop out (sorry, only way I could think to describe it :p) I'm worried that some substrate might get stuck to them and cause problems when he pops them back in, does anyone have any suggestions for a different kind of substrate that wouldn't happen with?

Reptile carpet. All substrates that I know of come in varying sizes of particles, which CAN get pulled inside when males evert their hemipenes, but when you think about how they live in nature, chances are very small that dirt and substrate particles getting pulled inside would cause problems. It certainly happens from time to time, but they way nature has designed their cloakas, most of what sticks gets caught and wiped off on the edges of the opening.