My little man is 11months and exclusively bf and is a right boob monster. I try throughout the day to offer water but he just isn't interested. I've tried different cups and have finally settled on a straw nuby cup which he does like. He will take 2 swallows of water but then anything else he takes after that he just spits straight out. He ends up covered in water - is this normal? Should I be worrying about how little water he takes?