With the help of a university student couple and their male friend found at an onsen, this project to investigate university students' sex drive has finally reached its fourth installment! This time, it's another big-breasted special! The mission secretly conveyed only to the girlfriend is '100,000 yen for each in-the-vagina sex session with her boyfriend's friend while he sleeps!' In this situation where she absolutely must not wake up her boyfriend, the university girl's lewd body becomes more sensitive during sex with her boyfriend's friend! She shakes her breasts and accepts multiple in-the-vagina sessions!
