My advice...
1)DON'T take the whole 50 mg pill, at least not the first time.
2)If you're on ANYTHING else that could (or does) raise blood pressure (most gear, thermogenics, etc.), DOWN the water, to keep it relatively lower...
3)Take it on an empty stomach, not with food...
4)Be ready...to...be ready...within 20 minutes or so, after each "round."
5)Be sure she's not going to fall asleep after the first (or second) time, 'cause it's GOING to get hard again, even if you don't want *it* to...
6)ENJOY!