It is very difficult to find a dress that fits my slim 11 year old daughter. This (and other CC shirts I've found on Ebay) fit perfectly! He can tuck it into his pants and it won't be too bulky, or he can wear it loose with a nice pair of jeans.
Van Heusen Sleeve Dress Poplin
42 Review
Star Wars, Marvel, and Disney Short-Sleeve T-Shirts for Boys from Amazon Essentials
50 Review
Kid Nation Kids' Tagless Long Sleeve V π Neck T-Shirts 4-12 Years - 2 Packs and 3 Packs
45 Review
Boys 3D Graphic Hawaiian Aloha Short Sleeve Dress Shirt Tops with Button Down - Sizes 2-8 Years by Uideazone
47 Review
Boys' Adidas Active Sports Tricot Athletic Clothing
45 Review
π₯ Stay Warm and Active with Rocky Fleece Thermal Underwear Bottoms for Boys
44 Review
Arctix Youth Pants Reinforced: Large Boys' Clothing for Active Adventures
46 Review
π Bold Pack Sleeve Active Hoodie Sweatshirt Set for Boys' Clothing - Stylish and Comfortable!
47 Review