Introducing water in an open cup or straw cup is great for oral development. Start by using an open cup filled 3/4 full, bringing it to the baby's lips and tilting it just enough so the water touches them; let the baby initiate the sipping so they can control the flow. For straw cups, it can take consistent practice—try modelling the motion with exaggerated sips yourself, or use a straw cup that releases water when pressed to teach them the connection between sucking and water flow.