the belly of the cook should be dry for beat eggs to fluff well (paraty).

talking, changing hands while beating an egg, changing people, or changing the direction of the beating, will cause the eggs not to fluff well.

looking at someone beating eggs will cause eggs not to grow  (cabo frio).

eggs beaten by a pregnant woman will fluff more (itaguaí).

however,  an egg beaten by a menstruating woman does not grow.