Making it short

I was sitting in one of the two armchairs, as I heard her enter. She didn't notice me at first as she came into the large room. She just saw me as I got up and stood before her.
"What are you doing here?!" she barked at me, in a very arousing mixture of surprise, shock, fear and anger in her face and voice. I wasn't even sure if she did recognize me after our first meeting. She was one of those who didn't even granted you to have an own face as a simple worker. She probably regarded the locksmith as a tool that only existed to open her door. Really a wanton, stuck-up bitch.
"It is easy to explain." I said, before I quickly hurled her facedown into the armchair, my hand at the back of her neck, suffocating her scream by pressing her into a cushion, while I put my knee on her upper arm to fix her. I started to slap her butt with my bare hand as I spoke on.
"I am here to teach you a lesson, and I see you really need it."