I was surprised. A feeling of fear mixed with excitement was flooding my mind. I knew she was inexperienced, but the confidence in her eyes mixed with the devilish smirk on her face were sending me in a trance. I couldn't say no, despite of the fear. She came close to me, sat next to me and rested her hand on my thigh. She whispered to my ear

'I promised I will make you a good boy' and kissed me. 'Now over my lap.'

I couldn't say no. I bent over her lap. I was still wearing my pajamas and, in that position, my erect dick was pushing hard on her thighs. She started caressing my butt through the PJs and the anticipation was killing me. I didn't even know what the injections will be. Then, I felt her hand pick gently the elastic at the upper base of my PJs and roll them down to my knees.

She was smiling.

'Last time, baby, you had your chance to play with my ass. Now, before you receive your treatment, it's my turn.'

WHACK! WHACK!

She started spanking my ass. My sense of nervousness was redirected towards the spanking as I couldn't anticipate when the next hand will be coming. After 40 or so, I buried my face in a pillow. She stopped.

'We don't want to make it so sore so soon.'

She started again to caress my ass. After a couple of minutes, she told me to get up. She grabbed the syringes and vials and then my hand and took me to my parents' bedroom. I was wondering why. She opened the door and I saw the reason. My parents' bed had a metal frame around it. There were four restraint handcuffs, one for each hand and leg, each tied to the half of the space between the middle of the frame and its respective corner.

'I want you to feel how it is to have no control baby. Don't worry, I will be gentle with you, but it will hurt. I know you will like it'.

I was started to get nervous again.

'I you feel you can't handle it, use 'red' as a safeword. I will stop. But remember, we won't do this again than. You have a choice, you either are 100% percent my good boy or not at all.'

I nodded. I said in my mind that no matter what happens I won't use the safeword. It was my first chance to have my fantasy put into practice.

'I promise you that if you wait till the end you'll receive a surprise' and she smirked. My dick was already getting hard.

She told me to get rid of the top of my PJ's and leave the pants on, for now. She will handle them. She helped me into my restraints, making sure make face and legs war reversed towards the classic bed position, so I could still watch her preparing my treatment. She made sure I were firm enough but also that they weren't hurting me and she put on bellow beneath my ass and one for resting my head.

Then I saw her putting some gloves on. She picked a small plastic bag from her backpack, with a thermometer and a bottle that look like a soap bottle. She than turned towards me.

'I will first take your temperature. Rectally.'

My heart was already racing. I wanted to tell her to stop, but I remembered our deal.

'I know you never had this before, so I will take good care of you, baby. I will have to stretch you a little. Now, be a brave boy.'

She came next to me. I felt her come near me and roll my pants. She sprayed the content of the bottle(which now I was definitely sure was lube) on her hand and some between my ass cheeks. It felt warm

'I warmed this up before coming specially for you. Relax baby'

She started massaging my hole, circling around it. It felt extremely good, I was starting to relax. She continued for a minute or two, until she thought i had enough

'Ready?'

And I felt her apply pressure. I started pushing my hips forward and instinctively squeezed my ass. She spanked my ass cheek hard. 'I said be good. Try to relax'. She again massaged my hole for a minute or so before giving it another try. I relaxed myself. It hurt as she was trying to squeeze her finger inside me. Then it suddenly popped in. As she was trying to go forward, it felt a little uncomfortable.

'Relax, love. Wait until I reach the end.'

The end of what? I was wondering. Then, when the finger was almost full, she started arching it and massaging something inside of me. I realized it was my prostate. I started to enjoy myself and moan. She paid close attention to me and started to move faster. The sensation was something I never experienced before. I was begging her not to stop. As I thought I was reaching for an orgasm(didn't know if I could orgasm from that, but it sure felt like I could), she removed her finger and spanked my ass hard

'You don't deserve your treat yet!' she laughed

She took the thermometer and the lube. When she inserted it, it felt a little cold but didn't hurt much. As we we're waiting for the read, she started preparing my first injection. She grabbed a syringe and a vial.

'We'll start with something easy. B12. It will help you get used with my special technique' she smirked

She started drawing the red liquid from the vial. The needle didn't look that big, but I was already started to get nervous. She grabbed a disinfectant wipe and started to wipe my left cheek.

'Ready?' she asked and I heard her uncapping the needle.

I didn't have time to answer. Instead of a quick jab, I felt the top of the needle pressing over my skin, making it sink. Then, in a few brief second, my skin popped and the needle got inside. She pushed it in slowly, making each little push hurt. I started to bite my lip. When it was all in, she started to inject the liquid. It did hurt a little, but nothing I couldn't handle. She took the needle off and started massaging my ass. I really got excited.

'Did you like my technique?' she asked

'9 out of 10' I replied

She smiled, caped the needle and removed the thermometer inside my ass. 'Her devilish smirk returned on her face.' I'm not sure you'll say the same for the next ones.'

She went back to the desk and opened another syringe. The preparation for this one was the same as the first one, although the color was a little different.

'This is a complex of multivitamins. It will surely make you feel better, although the distilled water I used will make it hurt a lot more. '

She then opened the last syringe. I panicked. The needle looked way bigger than any of the two used before. She started drawing a white liquid. I knew what that was. 'Ok baby. This last big boy will surely help end your cold. It will hurt A LOT.'

She got two disinfectant wipes and went to my back. 'Where do you want your first one?'

Fuck. My heart started racing.'Left ' I said. I wanted to let the 'big boy' have the right ass cheek for himself. She started wiping one each bellow the place where I had my first one. I heard the needle uncap and then felt the JAB in my left cheek.

'I saw you were a little scared, so I will give this one a break from my special technique. Now, be good.'

She started injecting and I felt my ass catch fire. I borrowed my face inside my pillow. I wanted to scream to her to stop. I didn't think I could resist another one. My restraints were being forced and she felt the tension in my muscles. 'Only a little more baby. Hang on.' She finished it a couple of seconds later. I could still feel my ass burning when she removed the needle, capped it back and started to massage the spot of my injection.

'This last one will hurt a lot baby.' said she as she was massaging my sore bottom with the wipe. 'If you feel the need to stop it is ok. But say it now, because if you cry or beg me to stop during the injection, know I won't. I won't let you treatment half done. Also, know, for this one I will use my special technique.'

He eyes were focusing on me. I was scared but excited after my last experience. I didn't want to end it now.

'Ok baby, let's do it.'

She smiled and started wiping my right ass cheek. I heard her uncap the needle. 'Here is goes!' and the needle started pushing on my right cheek. It started to hurt a LOT as it finally popped and went deep inside my muscle. When it reached the end, she allowed me a short break.

'Be a brave boy now.'

She started pushing the liquid, and I buried my head inside my pillow. I felt that the liquid was trying to burn my whole butt. I couldn't handle it. 'Please, stoop. I can't. Pleaseee!'. Tears started coming out of my eyes. 'Almost done baby.' But the pain kept increasing. Finally, she took the needle out of my burning bottom and started to massage it.

'I know it hurt!' She capped the needle. 'You've been a brave boy and you deserve a reward!'. She kept massaging my ass for another five minutes. When she was done, she removed my restraints. She told me to lie on my back as I was about to receive my reward.

She turned her back to me, removing something from her backpack. She came back with the bottle of lube and small vibrator in her other hand, having already a condom on it.

'Now baby, don't be scared. You already experienced some anal earlier I saw you enjoyed it. I want you to have your first prostate orgasm now. Trust me, you'll surely like it.'

It decided to give it a go. It did feel enjoyable earlier and sure it couldn't hurt worse than the penicillin. She told me to grab my knees and pull them upwards so she could have a nice view on my ass. I complied. She started slowly licking my hole with her tongue. I started to moan. When she felt I was ready , she lubed my ass and the vibrator and started pushing it slowly inside me. To help me relax, she took my dick in her other hand. After a while, it popped in.

'Now, baby, your surprise is ready.'

She activated the vibrations and my prostate started to dance. At the same time, she took my dick in her mouth. I started to moan. I couldn't control myself. After a couple of minutes, I started shaking. I finished inside her mouth, filling her with my cum.

After we took a shower, we got in the bed and slept together, she resting her head on my chest. I was wondering how would it be if she would get the cold from me and then there would be her turn to be the patient..