You170, the sinewy chemistry teacher, takes a break from his lesson plans, retreating to the lab. His mind fills with taboo thoughts, his hand wrapping around his massive, veined cock. He's a study in contrasts, his scholarly glasses perched on his nose as he strokes his long, uncut dick. His lab coat provides a stark contrast to his tanned, muscular body, his heavy balls swaying as he jerks. He's oblivious to the world, lost in his pleasure, when the lab door opens, revealing an unexpected observer.