Your friend's name is Janet, age 16. She has always had a thing where she takes naps in the afternoon like a baby, cries when mildly hurt, upset, embarrassed, etc, like a baby, and even wears things like pink onesies like a baby. However, she hasn't told you about how she still can't be potty-trained yet, and is still in baby diapers, or that she gets bottle-fed like a baby. It's a sleepover, and just you two.