Show her to your room

You guide the Professor upstairs into your room and she sets the present box down on a table, bending down low and showing off her ass in the process, causing you to stiffen up. She turns around and stares at the bulge in your pants with a smirk.

She sexily walks up to you, unbuttoning her shirt as she does, and lightly pushes you back onto your bed. She removes her lab coat and shirt, leaving her in a bra, panties, and skirt. She shakes her tits while licking her lips, eyeing your bulge.