drink lots of water for several days and don't jerk off.  You will drown the lady in cum.

Eat your veggies.
Eat food high in iron.
Increase water intake.
Take multivitamins.
Oysters DO increase sperm count due to high amount of zinc in them.

Purchase rocket pack for sperm to help increase power.

You can increase volume dramatically with Maca, a supplement that's available in most nutrition shops.  GNC carries it under the name Maca Man.

Stuff will make you shoot like a porn star.