Originally Posted by wiki_de_ghost
AndyJ, I use a 2.25in diameter tube and I always shave. My concern is to know which is better: pumping pressed to my abdomen or covering the tube opening with the silicon and using the silicone’s tight hole (I’ll have to use lubricant with this one). Which is more effective.
They’re equally effective.
Quote
I am new to pumping.
As Big Finisher noted, that’s an extremely large tube, though it’s a very common size. Unless you’re also extremely large already, the big tube will allow uncontrolled expansion to the sides, pulling lymphatic fluid in between the tunica and skin, causing bloat or "doughtnut", which is generally considered undesirable. A tube that is only slightly larger than your erect shaft size lets you concentrated on length work without being limited by bloat.
This thread tells how to size your tube:
Selecting Your Cylinder Size
An oversize tube will work, it just limits the amount of time you can spend under vacuum.