A boy and his son

Nathan: “Now let’s think about what we learnt from watching Nanny McPhee. What do you say when you want something?”
Tristan: “Please?”
Nathan: “That’s right. What do you say when someone gives you something?”
Tristan: “Thank you.”
Nathan: “And what do you say when you realise your head’s about to explode?”
Tristan: “Someone please help me!”