Also, something can stand for Furiously Beating Off depending on the context, but honorable men can differ.
"Excuse me for a minute my friend, I must go and FBO."
–adjective - (pertaining to an event or activity on the social networking website Facebook) intended for the notice of the public and performed or held on behalf of officials or of an organization
"Looks like Harrison and Ashley are definitely broken up. Both of them are single on Facebook. It's F.B.O."