A young 19-year-old brunette college student with shoulder-length straight dark brown hair, deep green eyes, pale skin with light freckles on her cheeks, small straight nose and full natural lips, is sitting at her desk in the middle of a crowded university lecture hall during class. She is wearing a short plaid skirt and white button-up shirt. Her legs are slightly spread under the desk. She has secretly inserted a thick pink realistic dildo into her pussy and is slowly moving it in and out with one hand under the desk while trying to keep a straight face. Her cheeks are flushed, lips slightly parted, and her breathing is heavy. Around her, other students are sitting at their desks, some writing notes, some looking at the professor at the front of the room. The lecture hall is full, bright daylight coming through large windows, typical student desks and chairs, green chalkboard with formulas in the background. Photorealistic style, realistic skin texture, detailed expressions and atmosphere of a normal university lecture.