In a baby-shower game, melted chocolate is commonly smeared inside a diaper for guests to identify by smell.
The game is a humorous imitation of checking a real diaper. Organizers melt different chocolate bars or varieties, place them in disposable diapers, and ask guests to inspect or smell the contents and identify the candy. The winning player is usually the person with the most correct guesses.
The activity is popular because it is inexpensive and easy to arrange, but it is not a universal baby-shower custom. Some hosts avoid it because guests may dislike food being presented in a diaper, while others use wrapped candy or a written quiz instead.
The game is sometimes called “guess the chocolate” or “dirty diaper,” and names vary by region. Its purpose is entertainment, not teaching infant-care skills.