What an idea

A small boy is sent to bed by his father. Five minutes later.... "Da-d...."
"What?"
"I'm thirsty. Can you bring a drink of water?"
"No. You had your chance. Lights out."
Five minutes later: "Da-aaaad....."
"WHAT?"
"I'm THIRSTY. Can I have a drink of water??"
"I told you NO! If you ask again, I'll have to spank you!!"
Five minutes later......"Daaaa-aaaad....."
"WHAT!"
"When you come in to spank me, can you bring a drink of water?"