The subtle conditioning taking place.  As she is spanked in her rear for the grinding.  It pauses her from doing such.  So that when  you entered, she had been still in obedience to your command.<br/><br/>Holding to this even when you began to slowly draw out and thrust back into her.  The only motion of herself, being what inertia you provided in rocking her.  As her breasts swayed with the slow thrusting.<br/><br/>Her fingers curled into the covers underneath her in response.