The new Seth Rogen film "Neighbors" has a pretty good lactation scene in it. Rose Byrne(sp?) plays a mother whose boobs are full and she needs to get the milk out and we get to see her full boobs complete with veins and she is complaining about her boobs hurting because they are so full. She even tries to squeeze the milk out herself but she lets out an adorable "ow" because it hurts so much. Seth Rogen eventually has to do it and we see milk spray out of her boob halfway across the room.