Bubo was a Frog-Dog and close personal friend to Jabba The Hutt. Though much older than Jabba, he often took the Hutt's lead in sticky situations. The two met when Bubo applied for a job as the doorman at one of Jabba's several nightclubs on Nar Shaddaa. During the interview, the pair enjoyed an extensive round of "oh you like that too", and were friends until their final moment.
By the time Jabba was leasing out his Palace on Tatooine, Bubo's position as doorman was little more than ceremonial given the droid at the front gate.