Nap time is a great way to start acting like a baby. Try taking an hour-long nap in the late morning or in the early afternoon. Newborn babies will tend to sleep sometime between 10.5 and 18 hours during the day, with a normal sleep pattern(of a few hours less) beginning at about 6 months of age.or many people, the idea of regressing into a childlike state is comforting, exciting, and perfectly normal. If you're curious about how to act like a baby, you can learn to talk, act, and dress like a baby for fun. See Step 1 for more information.