I’ve been using this turnkey clamp that MM found for months and love it. I get mine at Home Dipshit, but not all HD’s have them. I use the turnkey clamp as my "primary" clamp, putting it as far down the shaft as possible. Then, I put a regular cable clamp just above it. With the turnkey clamp screwed way down and the cable clamp closed as far as I can tolerate it, my cock stays very engorged for as long as I want.
I was doing the Brianrex routine, using multiple clamps for three 15 minute sessions. I’ve switched back to the doing five or more shorter sessions that last 8 to 10 minutes each.
I’m still using thick ~ terry cloth wristbands for wrap. Sometimes the little loops get caught in the turnkey screw, but I just unscrew a little and they get unstuck.
Karmaz:
This is the mag wrap to get, but they’re hard to find. Here’s a google search that might help.