I said you were getting good practice because when you and your future wife have a baby, you will spend at least the first few months waking up many times every night. It will be similar to checking your dick every half hour, but your wife will be there in a really crabby mood and you’ll be changing stinky diapers.
As a general “rule,” it’s dangerous to do PE when you can’t observe the results. If you’re asleep, or really drunk, or otherwise mentally incapacitated you are unable to see whether you’re injuring or permanently damaging yourself. If the in-flow and out-flow of blood is restricted to an appendage of the body — an arm, leg, or penis — tissue death begins to occur after 20 minutes. (Necks are one exception.)
I still don’t understand how you’re wrapping your penis with the cloth and duct tape, but if you’re wrapping your dick tight enough for the cloth to stay on, it is probably tight enough that you could get a boner, push a lot of blood into portion of the penis that’s above the wrap, and that blood would have difficulty flowing out when your erection subsides. Essentially, you’d be doing an extreme Uli in your sleep.
It doesn’t matter if you jerk off before bed. You still get plenty of erections in your sleep, or should be.
So, you’ve heard all the precautions, and you seem to be doing this with your eyes wide open — for much of the night at least. Let us know how it goes.
I’m always haunted by the memory of some 4H kids that visited my second grade classroom years ago. They had this cute little black lamb with an 6 inch tail. Down by the base of the tail they had a hose clamp cinched tightly around. Someone asked what that was for and they said it was to bob the lamb’s tail. After a while the tail above the clamp would die and they’d just chop it off. Fairly painless for the lamb, allegedly. But I think of that every time I wrap my dick up tightly enough to restrict the flow of blood.