I had just come home from my freshman year of college.

My stepmom, Elizabeth, told me she got a call from our doctor’s office saying I was behind on a few vaccinations, and that I needed to get them done ASAP. I was hoping my stepmother scheduled an appointment with an adult doctor instead of my pediatrician, but I was out of luck. She liked my pediatrician too much, and she said they told her I could see him until I was 21, much to her delight. I HATED shots, and I hated going to the pediatrician. My pediatrician’s office only took temperatures rectally, and I couldn’t remember a time where a shot went anywhere besides my ass.

The morning of the appointment, I got up and got ready to drive myself. However, my stepmom intervened and insisted on going to the appointment with me. We got in a big fuss until she threatened to spank me. I didn’t believe she’d even try, as I was 19, and she was 34, but I sure didn’t want to test her either.

We got to the clinic and checked in. The young girl working the desk told us to have a seat and that a nurse would call me back shortly. After about ten minutes, a nurse called my name. I was foolishly hoping that my stepmom would wait in the lobby, but she insisted on tagging along. I followed the nurse back to an exam room. She introduced herself as Carol, and told me to have a seat on the exam table. Elizabeth sat down in the chair facing the exam table. “Looks like you’re just here to get 3 shots today” Carol said as she glanced at her computer. I gulped. I couldn’t remember getting that many shots in one appointment since I was very young.

“We just need to take your temperature first. You know the drill dear, drop your pants and lay down on your stomach” Carol said. “I’m in college, can’t we please take it in my mouth?” I begged. I glanced over at Elizabeth who shot me an angry glare. Carol said no, and that she was sorry as she opened a drawer and pulled out a large jar of vaseline and a rectal thermometer. I stood up and unbuckled my jeans and slid them down to my knees. As I stood there in my briefs, I began to lean onto the table to lay down. “Go ahead and slide your undies down too dear, I need your bottom to be bare” Carol said. I slow slid my briefs down, revealing my bare ass, and laid down on the table. The table was cold, covered in the thin, crinkly paper that my junk was pressed against. “I’m just going to go ahead and slide your pants off - you won’t need them for a little while anyway” Carol said. The hell!? I thought. Carol grabbed my pants and underwear that were bunched up at my knees and just yanked them right off, handing them to my mom. Now I was really half naked, and extremely afraid. I was being afforded absolutely no dignity, even though I was an adult at this point. “Relax your bottom honey, this will be a little cold but it won’t hurt” Carol said. I looked up in the mirror and watched her dip the thermometer in the tub of vaseline. Then, I felt her spread the inside of my butt cheeks with her free hand before she slid the thermometer home. It gave me goosebumps, and it wasn’t long before I was hard as a rock beneath me. I laid there silently as Carol made small talk with Elizabeth. After a few minutes, she pulled the thermometer out. “Let me go get those injections, I’ll be right back, just hold tight” Carol said. Then she left the room and left the door wide open! I was bare assed on the table for all to see. “Can you close the door?” I asked Elizabeth. “I’m sure she’ll be right back” she said, staring at her phone. I groaned as I waited nervously, hoping no one would walk by and see my bare bottom. Then I saw a nurse walk by, along with a girl around my age and her mother. The nurse didn’t even look my way, but the mother’s jaw almost hit the floor! I closed my eyes, as I didn’t even want to see anyone else look my way. After another minute or two, I heard the door shut. Carol was back with three syringes and 3 vials neatly laid on a tray. She sat the draw down on her rolling desk next to her target, my tight ass. “You may be a little sore back here tomorrow, but these won’t hurt” Carol said. For once, I somehow accepted these comforting words. Soon I’d found out that it was a straight up lie.

I looked up as Carol drew up the first shot. The medicine was thick and opaque. “Now this one is gonna have to be slow, the medication is a little thick” Carol said, holding up the horse-sized needle in the light. I glanced up in the mirror and exchanged eyes with Elizabeth. I swear it looked like she was enjoying this as she watched my pale bubble butt, helpless and bare as could be on the table. I caught a whiff of alcohol as Carol wiped down my right ass cheek, and I twitched briefly with anticipation. “It’s really important that you try to be still and relax, or else you’ll make it hurt” Carol said. I formed a white knuckle grip on the edges of the table, I was so nervous. I thought about all the shots I had endured in the past at the clinic, when the nurses would have to group up to hold me down. “Mom, why don’t you come hold his legs. I would hate for him to flinch and make this hurt” Elizabeth clarified that she was only my stepmother, but she happily obliged. Carol had her hold my legs down by holding my knees down against the table. “Just try to grin and bear it sweetie” Elizabeth said. Easy for her to say. I thought about the roles being reversed and then I was instantly hard as a rock once again. My daydream was interrupted by Carol “Here she comes!” She said. I closed my eyes and squeezed my grip. Then I felt the thick needle pierce the center of my butt cheek. “Oh!” I whimpered. I felt Elizabeth push harder against my legs. Then, it felt like someone began pouring lava on my ass. I yelped loudly and opened my eyes to see Carol slowly pushing the medicine in. It hurt like hell, I couldn’t hold back my whimpers and squeals. “It hurrrrts….OHHHHH it hurts” I pleaded as tears formed in my eyes. What felt like 5 minutes was probably 15 seconds. Carol pulled the needle out and asked Amanda if she would massage the injection site while she prepared the next injection. I could feel the massive bulge in my butt cheek from the medicine. “Relax your heinie” Elizabeth said. I hated that word. It made me cringe, and feel like I was still a kid. However, I did try to relax my butt cheeks so that my stepmother could massage them, even if only for a moment. She gripped and kneaded my tight ass cheeks like she was making fresh dough. This certainly didn’t help my erection, which was rubbing against the table beneath me. However, she soon stopped, which reminded me of what was coming. I was dreading it. My ass already hurt. I opened my eyes and looked at Carol, holding the glistening needle up in the light. It was just as big as the last one, with maybe a tad less fluid, which wasn’t as opaque. Then I smelled the rubbing alcohol on my left ass cheek. I flinched as my stepmother held my knees down once more. Without warning, Carol jabbed the needle into my tight little bubble butt. I yelped as my other ass cheek was now burning hot. Thankfully, she only had to push in the medicine for about half as long as the last shot, but it still hurt like hell. “Last one” Carol said as she drew up a thick, purple goo into her last syringe. “Deep breath for me now” Carol said. I inhaled deeply, and before I could exhale, she stuck the biggest needle yet into my rear. I couldn’t hold back a screech as Elizabeth held my legs down tight. Carol didn’t let up, pushing the thick fluid deep into my ass cheek one last time. This one definitely took the longest, as tears began to fall down my face. My ass hurt so bad. Finally, she withdrew the needle and told me I was good to go. “He may not like sitting down for a while” she chuckled. I was embarrassed once more as I stood up with my cock still rock hard. Elizabeth handed me my pants and my underwear as Carol exited. It hurt to move my legs, but I moved as quick as I could to cram my bulge back into my briefs and cover my nudity. The ride home was quiet, but I could hardly wait for the evening. That night, as soon as I knew my stepmother was asleep, I stripped naked and laid face down on my bed. I stroked my dick with my bare ass in the air until I came so hard I was shaking, as I relived the experience one more time.