Hi Addictedtocockncum, what I found is they need space to expand into, I used a glass jam jar with a narrower neck than body, then drilled a hole in the back with a masonry drill and water to cool it, I then epoxied a pipe onto it and sucked with my mouth and bent the pipe over and pushed it into a slightly bigger pipe to hold the vacuum while I kept them hot with a small fan heater and watched them slowly fill the entire jar over +/- an hour, sucking on the pipe as I felt the vacuum decrease as my balls replaced the vacuum. This might just be me, but I found about a week to two weeks later that I hit this emotional low patch which took about two weeks for me to feel ok again, I tried energy drinks, extra vitamins etc, but that low level depression would not leave until it had done it`s time, which as I said took about two weeks to subside, it`s probably just me but I started wondering if it was messing with my hormone levels and stopped after about 3-4 times as I am prone to hitting a depressive state every now and then if I don't watch and control it, but I would like it if anyone reading this reply could tell me if they have experienced the same thing after pumping their balls, or maybe have a person in medical could tell us if it is possible at all. Have you found anything like what I explained Addictedtocockncum? I have to say it does feel amazing to hold these massive things in your hand, they feel so ridiculously big and stupid as they bounce off each thigh when you walk, I totally agree it does feel great.