Wonder aloud if dogs have knees. Get up on all fours and try to see if you can walk like a dog. Demonstrate how you would lie down if you were a dog by collapsing onto your stomach. When 14 year old boy runs from room, chase him on all fours, making arf arf noises. 14 year old boy will go nuts.
Say Yup to whatever 14 year old boy says to you. Use tone of voice to indicate questions, surprise and nonchalance. When he says, "Mom is a reeee-tard," say Yup and laugh. 14 year old boy will go nuts.
Wear pink camouflage surfer board shirts and giant 80s T-shirt saying Leave Me Alone in neon pink and green letters to pick up boy. Suggest he go into store with you. 14 year old boy will go nuts.
Who says having teenagers can't be entertaining? Sometimes it's entertaining as hell.