I once received an e-mail with all the kinds of masturbations. It was funny.
1- You're alone at home, and you masturbate just because you're alone.
2- August night. It's really hot and you can't sleep. You masturbate.
3- You're seeing the worst porn film ever made, but it would be a lack of respect towards the actors if you don't masturbate
4- You've just awaken with a big erection. You don't want to miss this opportunity and you masturbate.
There were up to 13 kinds, but:
a) I don't remember
b) I don't know how to translate it from Spanish
......... YOUTH: The period in life when one tends to think that the act of masturbation is something ephemeral