Ballpumping forces fluids into different tissues at different rates. The testicles enlarge faster than the sac, just as the core of the cock enlarges faster than the skin. So if you pump a short session, you'll get big eggs hanging in your sac. If you go for a real long session, you'll get a big bloated "grapefruit" sac.
when you bring home a chick that you havent brought home before and you bang her silly, and her pussy resembles a fish in either look, feel, taste, or smell