i'm not kidding about the Arginine, I've used Kamagra (same ingredients as Viagra) before and I found Arginine better as it was more gradual and gives a natural result without the negative side-effects.
Arginine increases nitric oxide (NO) which is why it used as a supplement to increase pumps at the gym, as it expands blood vessels, increases oxygen in blood and improves blood flow, but also without increasing blood pressure.
Taking 2 grams will definitely make a noticeable difference. Combined with Tribulis and ZMA it's even better.
The only people who are not recommended to use Arginine are those with herpes or those who show symptoms of herpes as it could cause a flare up. However, many people have herpes but never show any symptoms, even with Arginine.