The protagonist is an ordinary social person with a huge penis. He lives with his sisters at home. On the surface, they have a harmonious relationship between the siblings, but the undercurrent of desire is quietly growing... What happens there?

The protagonist is an ordinary social person with a huge penis. He lives with his sisters at home. On the surface, they have a harmonious relationship between the siblings, but the undercurrent of desire is quietly growing... What happens there?