I always use V. Always. B/C most of the time, I can't get it on with providers otherwise. I use 100mg and it usually lasts until the next morning, if I want to. I get a prescription from my MD and then pay cash for it. The only thing I don't like about it is the side effects. I always get a head ache, stuffy nose and other shit, including sometimes an accelerated heart rate, especially when I drink at the same time. And I always wait until I am sure I get some, i.e. until she arrives or until I get there. No need to waste a perfectly good boner.