This work depicts his first naughty experience with his girlfriend's older sister. She loses her virginity and cannot stop getting excited about the naughty act with her sister. She is fascinated by her sister's sex appeal, and is confused and pleasured by her first time using oral ejaculation and toys. Forgetting her, his excitement rises unintentionally when he has a serious Nakadashi sex with her. You will feel as if you have stepped into the world of adults, and you will not be able to stop your heart from pounding.