One fine morning, I had the urge to third part to a story made from two unrelated images…
Luna steps into a quicksand pit. Celestia then steps in. She does not to help her sister, but help herself to
her sister. While playing with her sister, Celestia pushes Luna deeper and deeper in. As Luna climaxes, Celestia pushes her under (you are here). Celestia enjoys her own quicksand sink as she sinks deeper and goes under.
Paraphilias are a hell of a drug.