@mike Yep I’ve got one of those too, which I use on my thigh, or a bandage for round my stomach.
It’s the same for me as the thigh harness except I have to tape the tubing down else I find myself catching the loops that form in the tubing in my sleep… I really couldn’t get on with letting it roam free every night!
Personally I found it more difficult to sleep with it on my stomach than my thigh & my tubings not long enough for the arm option.
I’d suggest using bandages/tubing for the first week to try letting it roam free, or different locations on your body, then you can decide if you need a fancy holder, modified pj’s, etc.
I also found that when they gave it to me the sales rep had a wide range of wearing accessories available free for that day, & its likely something in that selection may be handy.