A cute bikini gal on Shonan Beach enters a challenge where the prize rises every time she makes a virgin man cum. His oversensitive cock gets hard at the sight of her swimsuit and erupts repeatedly as she strokes him. Turned on herself, she offers to be his first and suggests that bareback penetration may feel even better. The summer challenge escalates into unprotected first-time sex, repeated creampies, and 20 ejaculations in total.