Personalized Mouse: Be A Friend Toddler Long Sleeve T-Shirt. Mouse: Be A Friend Toddler Long Sleeve Tee - Charcoal, from "Dog and Mouse" by Michelle Nelson-Schmidt shows us that being a friend is the best thing you can be. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.