To ensure comfort in toddler sleep bags, choose soft, breathable fabrics like cotton or bamboo that are gentle on their sensitive skin. Look for designs like those from Hushabye, which feature hypoallergenic materials and adjustable features for a snug fit. Opt for sleep bags with smooth zippers and no snaps to avoid discomfort during sleep. Make sure the bag is appropriately sized to allow for freedom of movement while keeping your toddler warm without overheating. Finally, choose sleep bags with soothing, playful designs for added comfort and calm.