I have found that taking Lecithin supplements have worked VERY well for me. Better than any thing else I have tried.

Prior to taking Lecithin, I usually would shoot a fairly average sized load. Not bad, but I wanted to go bigger for the GFs sake. (she loves it)
Then I discovered Lecithin. I take two 1200 mg capsules every day, usually with breakfast and dinner. After only a couple of days I noticed a BIG increase in the size and thickness of my cumshot. I also take Zinc and drink lots of water. (Both of these also help) But I definitely recommend Lecithin. It's cheap, ($8 for 200 capsules) and is sold in every drugstore you can find.