Originally Posted by GARY LEE

Like in a couple of the previous posts don't jerk off or have sex the day before your shoot. If you can't keep your hands off it then take it up to the moment but hold it. That's right don't cum. Get it workin' but don't shoot the gun, save it for when your getting paid.
Also drink the day before, not alcohol stupid but lots of water. Anything that will help hydrate your body. Stay away from the booze. Take the money you got for your shoot and drink that night AFTER the scene.
One last thing, amino acids. L arginine is probably the most popular of fellow actors. This is a pill that is taken daily and not only can help your blood vessels relax which helps the wood factor of course but is also directly related to building many compounds in the body including...you guessed it, a big load of jizz.
Good luck in the sack.