Mother and son don't get along well and are constantly fighting. They have their usual heated argument, but the teasing of the son's virginity ends up delivering a painful blow. The son's anger gauge, having been exposed to the soft parts of Kokoro, reaches its limit. He chases his fleeing mother, teaching her body the hierarchical relationship. Despite her will to resist, he teaches her carefully and thoroughly over the course of several days so that all pain is replaced with pleasure... The mother is reborn as a proper sex pet...