Healthy sweat is like a dressing that enhances the flavor of a woman's body. It would be a waste to wash it off. Found on the street, a busty woman walking, a female college student playing tennis, etc. He carefully observes his target, and pounces after she has worked up a good sweat. Surprise and rejection, as well as the embarrassment of being sweaty, turn into pleasure, and before long, resistance fades and they begin to desire each other.
