Yes, this comes from a short story set during the period when C3P0 is wandering the desert - he stops to talk to the Almighty Sarlacc and it explains its position:

«So you keep calling me the almighty Sarlacc, which feels a bit cheeky, to be honest. Absolutely nobody has ever bothered to ask my opinion about anything before, and you keep feeding people to me without my consent. How exactly am I all-powerful?»  ―The sarlacc, to C-3PO