[BonitaDDs]

Large... Shouldn't it stay on easily if it was too small?

Well all the breast should be inside so I don't know when I use mine I lean my breast so the cup has my whole breast press against my chest I pump one first once I have suction then add pump the second on suction is hard at first.
No breasts only touches the bottom of the cups you done pump the breast in you put the breasts in loosely then hold the cups against chest and pump