I could never feel their bottom teeth because if they are latched correctly their tongue covers them. But when they got their top teeth it did rub and it took a week or 2 to get used to it. It was sore, but it really didn't hurt, I guess it was more uncomfortable than painful. But we did have some tmes he bit..that does hurt, but it hurts before they get teeth and do it too. But we got that stopped pretty quickly, thankfully.