And the pain/discomfort level is on the high side of moderate.
the stretcher I made has barrels on the side to expand the stretcher so that you can adjust the stretch in increments. I stretch out to my regular maximum for 25 or 20 minutes and then unwind the stretcher and twist my penis 360 degrees and re-attach the stretcher and wind out again until the discomfort becomes intense and hold for 10 minutes.
Sometimes I will continue to wear the stretcher outside of the bath as is dry off, but usually I like to keep the head calmped for no more than 30 minutes total, as tissue damage could result if I went longer.
I have worn the stretcher for as long as an hour, but recently I modified the head clamp and it`s much tighter now and so I won`t go more than 30 minutes.