My friend's mother

Arisa married her husband two years ago and lives with her step-son Taichi and her family of three. One day, Taichi brings two friends home. With Arisa's beauty in mind, their friends threaten, "Is it okay if Taichi gets bullied?" and play with her body. The two, who have come to the public with this act, come again later to assault Arisa. Then he tied up Taichi, who was there, and in front of him he naked Arisa...