Well, not sure if it's true - I've heard that it makes you hard for hours but it's not as easy to get rid of the erection after. I mean it makes you ready physically but it doesn't make you more horny mentally. So if there is someone who want's to have a hard on for 3 hours then go on try it. Although I can't imagine anyone who would enjoy several hours of nonstop sha*ging .
Nevermind the horrible dangerous chemistry and it's side effects. I think sex should be natural and if you are not horny enough to continue, then take a break. No point to try to prove what a man you are by using such shit.
Maybe I'm wrong but I thought they made viagra for granny's who cannot get up at all to enjoy few last rides and not for young guys to mess with it.
I definitely wouldn't appreciate such a non-natural erection. I prefer to make it hard by my own efforts and then enjoy the success.