Im looking for a way, that i will prevent myself from ejaculating while asleep.

I thought about banding to physically stop the cum but if i sleep for more then few hours i might cause irreversible damage.

My other idea was to shove a sounding tool in there, and try to sleep with it.

I can cum before i go to sleep, but then i miss the point of preventing myself from cumming for long time (im biulding it up perfectly, then wet dreams fuck it up) and keep teasing myself and just almost reach orgasm.

What's in ur mind? Have any experience?

A TIGHT pressure (like a handball forced against the body tightly) in the perineal region will create a retrograde ejaculation into the urinary bladder. Of course, you will piss it out in the morning... and you will still orgasm...