It is immature to keep training wheels on your bike.
Nick, who still uses training wheels on his bike, is invited to go out and ride with some of his friends.
Nick wants to join his friends in a bike ride.
Nick takes off the training wheels and goes out riding, although he's a bit shakey.
Nick goes out riding with his friends and keeps the training wheels on in case he falls.
Nick takes a few falls while riding but bonds with his friends.
Nick's friends see the training wheels, start laughing uncontrollably, and make jokes about Nick.