I’m using a PM as I write, and I am uncut. When I first started using it, I was very worried about stretching the skin majorly. (As I’ve said in other threads, I want an 8 inch penis, not a 12 inch foreskin!) But I’ve found that, if I pull the skin way back before I strap on the device (making me look “cut”), I pull the penile tissue itself and not the skin, at least to any large degree. Still, I have to admit, the two ADS-type devices that I use seem like they would work better for cut men. The foreskin is such a pain in the ass sometimes.
But I reckon that if you wanted to use the PM to stretch the foreskin back (as in foreskin restoration), it would be easy to do. Instead of pulling the skin back before strapping on the device, you’d simply pull the skin forward so that most of the work of the device would be stretching the skin and not the rest of the penis.