I'm close to 50 now and have been using Viagra 100mg consistently for every appointment. It works because it keeps my erection for the full hr session. The only problem is, my refactory period takes 24 hours. I've cum half and hour into the session and my cock was still hard as a rock, but because I had no round in the chamber, it really didn't matter that my cock was rock hard. This is a case by case scenario. When I was in my early twenties, my refactory period was much much shorter and I was able to cum at least 3 times in an hour.