I got this via Pharyngula.  It is not for work, or in the presence of children.

OK, you might be OK if you have head-phones, but then people will wonder what all of the evil, subversive giggling is all about and you'll either have to say "Oh, nohing", which many people find unsettling in a subversively giggling co-worker, or you'll have to share, and that would probably not be good either.

Just save it for home alone time.

http://falafelsex.blogspot.com/2006/09/reasons-abby-is-going-to-hell-number.html