Mamava bava saagara

The other day my son asked me what does Mamava bava sagara means. I told him i dont know but sagara might mean 'Ocean'. Quick came the response "Why should we put uncle in the ocean?". I couldnt avoid a little smile on my face. Later told him "Mamava" doesnt exactly mean "Uncle". His translation made me smile but made me think as well. I shouldnt give him half baked information going forward.