Mantas don't like air bubbles???

I was told that I should swim always beside the Manta animal, never underneath it, due the air bubbles which the Mantas don't like so much.
In this case it absolute was different, because this Manta liked the bubbles very much and swam permanent over me. Once it let fall down some naturals on my body which was much much more than the shit from a bird from the sky.