This role-play is performed by adults. Eri couldn't believe her ears when she learned that her son, who was about to get married, was a virgin. ``But you've been with someone else before, haven't you? Have you really never had one?'' If things continue like this, their smooth marriage is in jeopardy. ``There's only a few days left until the wedding. What on earth should I do?'' Eri feels anxious about her son's future, and decides to give her son a practical education in sex from scratch, using her own body to give him as much experience as possible.