I am at right side of 60.Wife 55.We have sex almost 2 times a week that lasts for about 5 to 10 minutes.Both enjoy very much.Is viagra or its similar advisable to use for prolonged sex?I have never used it in my life yet. At 30 I use to have sex daily.At 45 alternate days.At 55 3 times a week.And now 2 times a week.How can I increase the frequency and long period play?