Message

[Gues]

Your bitchbot site has this in "about":

"Message system for leaving short notes for people who are offline."

In the commands reference, I don't see any command for using this?

[Rimfire]

Wow, nobody has replied to this! The OP has probably worked it out by now but there may be others looking for the same thing.

Botname, bitchmsg nick message (up to 160 charactors)

Example: If you wanted "mybot" to send  message to "Someone" to say you are looking for them you would type:

Mybot, bitchmsg Someone Hey I've been looking for you

The bot send a private message to "Someone" next time it sees them.