There are drugs that can be taken to increse semen output. Just ask any porn star! LOL, seriously though, Nolvadex is known to increase it. The actual drug name is Tamoxifen. Staying hydrated helps also.....the more water he drinks throughout the day, the more semen. It also depends on the last time your had an orgasm was....if it's been a while, you'll have more buildup.
Good luck!
Skarn
Good luck!
Skarn