No, it's her elbow, what does it look like?
Ohhh wait,
there, yup that looks like her arse alright
And what a fine arse it is.
IIRC Ducks had mentioned quite a while back that she had made the acquaintance of an agreeable gentleman whose interests included erotic photography. Methinks this is one of the results. Of course, we'll need to see many more to be certain ...