Brotha, get some ED medicine, jack off about 2-3 hours before you have sex... pop a pill, and booom doggy, your gunna be having sex for at least a hour, AT LEAST! garunteed!!! I use it all the time when I want to impress girls :D
HOLLA!
try this site man, swear... i use it all the time.
http://www.techresearchrx.com/