A pump with gauge is important, which is why I don't care for Bathmate products. If you don't know the level of vacuum you're applying, especially with water, it's really easy to go overboard. Somewhere around 5psi is safe and will be effective. Adjust accordingly. If you feel pain, find red spotting or other discoloration other than basic overall redness, reduce pressure.
Stay hydrated, which is just good health anyway. A gallon of more of water or other non-caffeinated fluids is a good daily intake.
Either air or water are equally effective. Your penis doesn't know whether the vacuum is air or water. Same with tube size...anything not touching the tube has vacuum applied to it.
Be patient. Don't expect length gains, and don't expect girth gains to be permanent for a very long time. Don't overdo time or pressure in hopes of speeding up the process. The temporary gains are fun if your partner isn't grossed out by the oddly different look of your penis. Enjoy it, or stop. Life is too short to waste time doing something you find tedious.
