Personalized Be a Good Boy T-Shirt. Show off your personality and spread joy wherever you go with the "Be a Good Boy" print design. Get yours today and embrace the fun! Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.