Sperm Bank - Sister Was Surprisingly Dangerous Too

A comedic adult simulation game about a NEET shut-in named Shingo who receives help from a quirky loan officer at a 'sperm bank' to seduce his visiting sister within a 14-day window. The game uses a stat-based system where you raise the sister's lewdness while lowering her reason through daytime interactions, item collection, and communication, with nighttime scenes unlocking based on progress. A side-story update adds a massage mini-game involving the mother. Features multiple H-scenes, stat tracking, communication puzzles, and a New Game+ recall mode.