Third step-son's Perspective. step-Mother imagined. Story: The step-daughter, while searching for her step-mom, catches her humping a pillow on the side of her bed. Oddly turned on, she plays with herself. When her step-mom eventually notices, she has her strip down and hump the pillow on the other side of the bed. They continue doing this, as the step-daughter describes how sexy the step-mom looks while humping her pillow, watching her young step-daughter grind with her until both of them reach climax.