Okay here it goes:
people who read this, remember it's NOT for newbies!
Opa's way of clamping nowadays:
step 1: Warmup in a hot shower, rly hot water, 3 minutes
step 2: get up to my computer chair, put the olive-oil aside
step 3: find a decent porno movie on the PC to watch while rubbing in my dick with olive oil
step 4: put on the adjustable cock-ring
http://www.lustfynd.se/images/product/original_68930.jpg this one, and get hard as hell, remember what time you started to clamp on in the porno movie (I only put the clamp on for 13-15 minutes max).
step 5: now it's time to work, get as hard as I can, the oil helps ALOT here.
Im taking my right hand and I clamp it around the base pretty tightly, with my left hand I squeeze my penis head so it's no blood inside it, the blood is now trapped between my right and left hand, which means in the middle of the penis.
step 6: I hold this for 1 minute, and if im losing alittle of my erection I start pushing up a little with the hand I clamp with (my right hand) so my middle girth of the penis gets a big expansion.
step 7: I do these manual clamps 6-8 times (all depends on how fast u can get hard after every 1 minute holding) , while being clamped with my penis ring aswell, which takes about 13-15 minutes.
Then I take my penis ring off and I rest 5 minutes and I start all over again. I do this 4 times. So 4x 13-15 minutes or something like that.
step 8: warmdown with hot water, 3 minutes, and finish with 120 kegels.
I think this is how exact I can be with my girth-routine. I do this 2 days on and the 1 day off, nowadays.

I hope you enjoyed the reading.