I've been autocircumcision for a bit now and the coin method seems to work best. I started with having the coin normally be folded, then I started to tape it with medical tape which also worked and now I have a coin on both the front (the one I can see looking down standing up) and one at the back where the frenulum is. This seems to work well and I'm happy with the progress I'm making
if anyone has any medical tape substitutes though I'd love to hear them