About 1962 - I hadn't been keeping it on purpose - it was just the first time a girl said "You can go all the way if you want". I had had several sexual affairs by then, it was just that I had never achieved an orgasm by actual penetration before. I don't think that I was very skilful, but the lady seemed to enjoy it and seemed to want it again (and again and again and again . . . . ) - it provided me with the beginning of the learning curve - and was very enjoyable - I hope mutually.