I'm with Dr John and average size man. His mouth size between the teeth is 2 inches. He wants to jot down some numbers and see how patient Penny's mouth compares to his. He hands me some items from the office that I compare my mouth too. I make fun of how puny and small his mouth is compared to mine. He loves my dark lipstick too. I measure the size of my mouth against the tape measure and leave a mark.