You could get a better Hanger. A sock and shoe string sounds painfully dangerous and I also don’t think it would be capable of hanging higher weights when you move up. A captains wrench is relatively easy to make, cheap and so much safer. There’s a few other instructions for hangers on here you can build as well that will work better for you. If you don’t mind spending a few bucks you could look into ordrering a bib Hanger or a vacuum Hanger.
That’s my advice on Hanger styles. If you insist on the sock Hanger I have a few questions. Are you using any type of wrap before applying your Hanger? Your tying off at your base? You should be attaching about an inch to inch an half below your glans. Attaching at your base will mostly just stretch skin. Oh. And NEVER NEVER hang with any type of erection. This is a 100% flaccid exercise. You’re going to fuck up your dick hanging with a hard on.
Do you have any previous PE experience before this?