There's a very popular page with the "Holy grail of cum load increase" where a dude took different supplements to see what works better.
What worked better for him was this combination:
(1) L-Arginine, 1000mg Strength, Taken 1 time daily = 1000mg
(2) Zinc, 50mg Strength, Taken 1 time daily = 50mg
(3) Pygeum, 100mg Strength, Taken 2 times daily = 200mg
(4) Lecithin, 1200mg Strength, Taken 1 time daily = 1200mg
I am currently taking Argenine, Zinc and Pygeum currently but just because I wanted to produce more precum. It's been only a week so I still haven't seen results, but will try for longer.