I was back to work the day after Misty treated my ear infection. The sting from the spanking had completely subsided, but there was a soreness - a knot in the muscle - deep in my left cheek. As often as I could, I discretely prodded the spot with my finger, recalling the immense pleasure of receiving the antibiotics injection. It had been years since I had a shot in the butt and now realized how much I craved them. I wanted to talk with her about how we might make it a more regular thing.

She texted me at mid-day, ‘Was gonna check-in on you later. You be home around 6?’

I sent back a thumbs-up and imagined what fun she might have in-store with the post-treatment check-in. I only beat her home by a few minutes and she suggested we move to the bed room. She inspected my ear and pronounced it much improved then instructed, “Lower your pants and lay face down on the bed.” I complied and she inserted a thermometer in my bum. I got excited when I saw her withdraw a syringe and vial of medication from her bag.

“It’s a vitamin cocktail. I get one myself every week and recommend the same for you,” she explained. Perhaps my telekinetic wish for regular shots had reached her? I was truly excited and felt myself getting hard, my growing erection pressed against the bed. “Here’s the spot from yesterday,” she quipped, swabbing the same site and then plunging the needle into my cheek. The influx of the cocktail seemed to reignite the fire of the previous day’s shot and again I felt the wonderfully deep, throbbing warm ache.

She withdrew the thermometer and I thought she was preparing to leave. I stood, my boner bobbling free, and began to pull up my pants. “Not so fast,” she reacted. “I have a dire need for a protein injection,” she explained tapping my hard-on with her finger tip. She shrugged down her scrub bottoms and panties and knelt on all fours on my bed. The view and invitation were enticing.

“Let me warm-up the target a bit first,” I replied, and picked out Delrin rod from my drawer of toys. I gave her proffered bottom six sharp whacks. I knew from personal experience this tool, while quiet, stung like crazy. Her sit-spots now sported a series of red lines and knelt behind her and slowing pushed into her wet, inviting vagina. She pushed back at the same time, developing a counter thrusting rhythm. This position always felt so tight for me and was usually dismayed at how quickly I arrived at climax.

This time was different, as I lasted until I was actually beginning to tire from the effort. I felt that wonderful approach to the edge and then a release of numerous pulses. As I withdrew, it was obvious that the volume was equally exceptional as a significant rivulet of cum oozed out and ran down her thigh. “That was soooo good,” she purred. “How about next week, I teach you to give shots and you can give me mine?”