Yes, I do edge with a cockring on, however I take it off about every 20 minutes or so and pound the clown for about 5 minutes to get some good, new, fresh blood flow in the unit. I then put back on the cockring, do a series of kegels to fill it with blood to the max and off I go again. There seems to be no impressive swelling during the first 1/2 hour. It is 45-90 minutes when you see the big, impressive, zuccinni effect. When it starts getting real big, I then do ULIs and just plain squeeze the shit out of it with an ok grip just like when I am jelqing.
Hope this helps.