This is how I work base girth.
Get 80% erect, then grip about 1.5 to 2" above the base area with an inverted ok grip with the right hand. The left hand should be behind the glans, to offer support for shaft.
Once your 80%, kegal in as much blood as you can, and clamp down tight with your right hand, while your left hand is supporting the shaft. Once you have clamped down, kegal and hold it, and move the right hand toward your pelvic mound.
What you are doing is basically kegaling against your right hand that is trying to force the blood back into the body! I have found that it really expands the base area!!!
The key to the success with this, is a good tight grip, and a strong kegal that will last the duration of the hand movement toward the body!Say if it takes 5-10 seconds to move the hand toward the base, the kegal would be held for this amount of time! Ever repetition should start with kegaling enough blood into the shaft so as to have something to help with the expansion.
I feel this beneifits, the stretching of the tunica at the base, and strengthens the PC muscle, and also makes the arteries at the base of the penis larger, which would be excellent for more blood flow into the penis. It works for me anyways! Good luck!!
Girthius