FryPup,
You have two options with the 2.25 inch tube:
1) You could pump both your cock and balls in this tube, if you want to expand all of your genital parts. This would be a good diameter size to accomplish that task. Or
2) You can cinch or tie down your balls when pumping in the larger cylinder.
Presently, I begin my pump routine in a 2 inch tube for about 20 minutes getting a good “pack” and without cinching down my balls. Then I graduate to my 2.5 inch diameter tube. I don’t have a 2.25 inch tube. As a newbie pumper, I initially made the mistake of buying the larger 2.5 inch tube. Now the larger diameter suits my goals for further girth expansion. But now I have to cinch down my ballsac, in order to prevent my testicles from being sucked into the tube.
I use a simple cut out circular section of rubber bicycle tubing - maybe about 1.5 inch wide or so. I twist the tubing, turning it more into a thicker,rubber ringlike shape. I pull/stretch it out to make it more pliable and then place it around my ballsac, separating the base of my cock from my testicles. That’s it. I put lube on the shaft of my penis and inside the cylinder and begin to pump. Also, I get some beneficial stretching downward action on my ballsac from the outside base of the cylinder pressing against my rubber tubing ring as I pump. Of course, you can come up with your own ideas on tying down the ballsac.
Other than the possibility of extra fluid build up or the “donut” effect in the region between the circumcision scar and the glans, I wouldn’t worry about uneven stretching of the penis. If you are still concerned about one area on your dick expanding faster than another, you can always wrap those areas with non-sticking self-adhesive bandage tape, therabrand, etc. during pumping or after you’re done.
Good luck.
Peforeal