Alright listen up soldiers [the Guru of constriction and string LOL] the MAX time is 30 minutes.....after that the tissues die from non-stop torniquet.
But I do 35 mins....HTF do I??? I have built my way to this over 14 months of doing these, plus I release the clamps slighlty if it gets bruised than re-tighten, also massage the area where I am clamped.
I really am a master at Torniquet exercises...they aint as easy as I say they are...while doing the exercises you must bare in mind to monitor the penis where its clamped, tied etc etc and if any bruises come [black marks] than ya too tight, release some and massage.
I would highly REC' doing this stuff infront of a sun-lamp which really helps ALOT to reduce injury.
Also NEVER use an elastic band, this could tear thru the penis as its very thin and would act like a knife at high stress....best thing is a cable clamp, with padding underneath...I myself dont use any padding...but bare in mind it hurts alot when you take the clamp of as any skin that was trapped gets to normal.
I would say for begginers....do 10 mins to start with for say 2 weeks than move to 20 mins and stay their for many months till ya ready [you will know] to take the 30 mins head on.
This tissue death is meant for a fresh fish outta water doing these right off for 30 mins....it would do alot of harm...but someone like me whos used to it...its no probz 'most of the time'.
Good luck all and any questions on constrictors, torniquet exercises and methods than just hit me.