We see her breasts, butt, and bush as she lays down on the stairs and the guy kisses her legs before making out with her.
We then see her emerging from the same door the next day, showing full-frontal nudity with only a robe over her shoulders as she walks back down the stairs, her breasts bouncing a bit.
Finally she and the guy disappear into a bedroom.
Finally she covers up when seeing unexpected company in the kitchen below.
She then continues up the stairs and the guy joins her in a hallway where he picks her up and she wraps her legs around him while making out.