10) We have secrets we need to expose to sunlight while preserving some anonymity.
9) We’re exhibitionists who get off on revealing in public what usually is private.*
8) We’re attention whores.*
7) Writing about (our) sex gets us hard, wet, off.
6) It lets us participate in a broader community centered on joyful, open love of sex.
5) We don’t know (any more) how not to.
4) We secretly (or not so secretly) think we’re better than all of you readers with your vanilla, mundane sex lives.
3) We’re genuinely proud of our sex lives, and believe the world benefits from knowing more about them.
2) We’re insufferable, self-important, ego-centric, narcissistic libertines who exist without benefit of either social filter or superego.
1) We hope it’ll get us laid (by our wives, husbands, partners, girlfriends, boyfriends, friends, or strangers).
* Note difference between an exhibitionist, for whom the thrill is in the act of the revelation, and an attention whore, for whom the thrill is in the attendant interest s/he is shown.