Question about skin stretch

I made another DIY vacuum hanger with bigger cap and bigger sleeve and it seems to work now. Vacuum is there and I can pull it with decent force without it slipping off.

When I try to take the hanger off, there seems to be some foreskin over the glans (upon pulling the sleeve off of the penis). However, while penis is under tension of hanger, I can move the shaft skin freely forward and backwards, so I guess the hanger is not actually pulling on the shaft skin and thus cannot cause turkey neck or anything like that?

Can anyone shed some light on this?

If everything is alright, I might start hanging as of tomorrow. :)