It's her OC Mistress Chloe Adore with her subs Twilight and Sunset.
This took longer than I liked to finish in GIMP. Everywhere I zoomed in, there was weak and/or dirty lineart that needed repair. Makes me glad I didn't try doing shading or a latex shine. Didn't help that the rough sketches became a bit too complicated to get everypony posed together right. Other than that, it seemed to turn out well enough.