Where plug BB into on acoustic amp when already using both channels?

When playing a gig at a Cafe using my Yorkville AM150 Acoustic amp for Guitar in channel 1 and vocals in channel 2 where do I plug BB in ?
There is no AUX input on amp, there is an effects loop on back of amp with send and return.
Do I plug guitar cable in BB than another guitar cord in channel 1 guitar input , as I would a guitar effects pedal in an amp ?