There is not enough evidence that ball pumping does or does not cause temporary or permanent sterility. Cock and Ball It makes sense that if you introduce lymph into the scrotum, the testicles will not be able to snug up close or hang away from the body to obtain the ideal temp for sperm production. It also makes sense that negative pressures may cause a disturbance in the testicle. Well humans, the time has come to even out that playing field down there and start BALL PUMPING. Simply pump you nuts and get them engorged with as much lymph as you can stuff in them. The best thing about ball pumping is that the only limit there is on how large you can pump is the capacity of your scrotum to hold the extra fluid and the amount of time you have to pump. These things can obtain grapefruit status if you let it. Ball Pumping - Equipment So you ready to get started in ball pumping eh. First thing you should know is that you CAN pump your balls in one cylinder, but it becomes a hassle when trying to keep that pesky penis from getting sucked in. Therefore, it is common practice to pump both Cock and Balls at the same time out of convenience. So what you will need besides a handpump is a cylinder to house both penis and scrotum. There are the three categories of penis and scrotum cylinders: Single stage cylinder Multi stage cylinder Specialty system A single stage cylinder is a cylinder that is made up of one part, or one cylinder. These cylinders are the most inexpensive to purchase and are considered entry level for beginner ball pumpers. Folks with large packages should consider a multi level cylinder or a specialty system to avoid genital distortion, caused when pumping huge packages in tight quarters. Here is Dr Joel Kaplan's sizing matrix to determine the best size penis and scrotum cylinder based on your current erect dimensions. Another option is PumpToy's LongJohnny which only comes in one size, 4" diameter, but has a seal at the base that restricts the opening to 2. Usually the multi-level cylinder has a smaller diameter base that contacts the groin, which then expands into a larger diameter cylinder. It is common for the larger cylinder to be 5-inches in diameter. An example of a multi stage cylinder is PumpToy's STJ cylinder - this cylinder has a seal that restricts the base to a 2. These multi stage cylinders are designed to ALLOW the penis and scrotum enough area to grow without smashing into the sidewalls. This design helps reduce genital distortion caused by this smashing. Specialty cylinders are proprietary and highly customized cylinders that are considered THE FERRARI'S of penis & scrotum cylinders. Doesn't sound like much, but these are real issues real pumpers run into when pumping huge. Here are the differences between the two cylinders, On getting stuck. The Monster-Tube product line is hinged so that after pumping your package to mammoth dimensions, one can simply unscrew the bolts and swing the tube open. The Bull Master product line already has a 4" opening but uses a flexible seal to go between the cylinder and the groin. When it is time to pull out, one detaches the seal from the cylinder and pulls the package out of the 4" opening. The gasket easily stretches around the package thereafter. The Bull-Master is already 4-inches in diameter, but have added pockets around the cylinder to house the penis and scrotum that measure a good 5 to 5. These pockets form the penis into the BullMaster mold so you come out looking like a champ. PumpToys make a larger version called the Bull-Master Magnum which is much bigger. Well that's all for the equipment portion of this article. I hope this article has been helpful in your quest to find the right tube for your size, expectations and budget. Ball Pumping Guide A few facts to understand penis and scrotum pumping (penis facts in blue; ball facts in red) The penis can handle higher pressure than the balls. The penis benefits from a lot of breaks and pulsating pressures while the balls do not need breaks and benefit from constant pressure. Since the penis and scrotum are pumped in the same cylinder, yet penis & scrotum pumping are much different, a happy medium must be met between the balls and the penis. As such, the ball pumping routine is: Your current penis pumping routine at lower pressures the balls can handle. Because of the lower pressures, you can adjust the schedule to lengthen the duration between each break and/or add more sets to each routine to reach the happy medium. This routine will take 1-hour and can be increased as your penis (and balls) get used to the pressures and time in the tube. Advanced ball pumping sessions run a minimum of 2-hours, but it will take some time and dedication to get to this. To begin, warm your balls up with a hot wet cloth or a heat pad, and stretch them out with a milking-style massage. Lube your cock and balls so the slide easily along the tube as you pump up. Lubricate the rim of the cylinder and the first inch inside your cylinder generously to help you seal. Insert your cock and seat your balls into the opening. Then pull a couple strokes on the pump to draw those balls into the cylinder and get an airtight seal. Begin your ball pumping regimen and pump to a lower and comfortable level. Your testicles will tell you when the pressure is too high. As we discussed before, ballpumping takes longer than cockpumping, but you have to be even more gentle. As your balls expand, they displace vacuum, so you have to pull from time to time to keep that pressure constant. In general, take a break every 15 - 30 minutes or whatever break based on your own routine to refresh the circulation in your cock and give your ball sac a rest. Reheat with the warm wet cloth or heat pad before you go back in. Complete the session in the same manner and when you are done, put those jewels in your hand and feel that weight. Advanced ballpumpers can reach 16" or more in diameter during their full 2+ hour session. You can expect the bulk of your gains to last 1-2 days, but you can expect larger than normal balls for about a week.