Eru, the sister of a loser in life who is treated like a delivery health worker by her brother. When his sexual desires build up, he summons his sister and forcibly shoves his bare penis into her mouth, or toys with her body that's still in development, then thrusts his hips into her tight vagina and pounds away. This day too, despite resisting her brother's penis, she ultimately succumbs and orgasms as a woman.
