I generally go with as much pressure as I can tolerate. I don't get how a guy could gain (he won't) without getting any expansion from clamping. I wrap flaccid, put my clamps on, work up the erection a little, tighten the clamps a little, get a little more erect and so on until I am fully engorged and the clamps won't go any tighter. It's not that difficult, but some men treat clamping like it's rocket science. If you can wrap, put clamp/s on and not get any expansion you are not using enough wrap. It should take all you can muster to snap your clamp or clamps closed to the point it/they won't close any more. You should also have teeth still showing on you clamp/s. I've seen some guys just go through the motions. They put on a clamp, get a little of a pressure feeling in their penis and think they're doing it right. Clamping is advanced, and it's supposed to generate more pressure inside you penis than anything you have used before. It's not supposed to be a cake walk, nor something that's easy. It WILL make your dick darker too when you're doing it correctly. That's part of the game.