M. M. kneels with her back toward the camera, bends over, and lifts her skirt up exposing a pink girdle (#1). She gives the camera a look. She straightens, lifts the prom dress even higher, and reaches behind her and grabs the girdle with her left hand (#2),  pulls it down her ass (#3), and spanks herself (#4).  She examines the self-inflicted slap mark on her rear. Why does she have a half-smile?