The first thing you noticed when you woke up from your slumber was the odd feeling your body had to it. You felt like you were a semi-circular shape stuck in another half-round shape. It was dark, humid, really hot and your hearing was muffled. It was only when you noticed your Sisters heartbeat, that you remembered where exactly your body was located.
"Phew, yesterday feels like a fever dream. How did I end up in this predicament?", you thought. It seemed like your Sister was still sleeping, since you didn't feel much movement beside the gentle waves of her breathing.
Though that changed soon. Soon after an elongated yawning, your sister sat upright in her hospital bed. Still half asleep, Serena slowly looked down her body. When she looked at her upper body, she let out a cute "Yelp!".
While she was lying down, thanks to your face basically making up Serena's whole Nipple, you felt like lying down too. When Serena got up, you had the experience of your world tilting. It really was like you were being pushed off a cliff, her tit's firm grip being the only thing stopping you from falling down.
The next thing you noticed was Serena's hand touching her boob. Or was she touching you? You really couldn't tell the difference, but it felt off in a weird way.
"yesss, this turned out even better than i could have imagined!", your Sis cheered. "Hey Tim can you hear me?", she whispered to her own boob.
You tried to reply to her, but you only got out muffling sounds thanks the the bandage covering your face. Noticing your small vibrations, Serena got out of bed and went to the bathroom next door, covering her tits with her bare hands on the way.
To you, her moving felt like a small to medium sized earthquake. If you didn't know about your whereabouts, you would be scared to death.
Arriving in the bathroom, she locked the door, went to the sink and began to remove the bandages that were blocking her nipples, and by extension you, from the outside world.
With a rather stressful ripping sound, you were revealed to the light again.
And the first thing you saw boggled your mind.
Standing in front of you was Serena's mirror image, half-naked pointing to her chest.
Her boobs were enormous! Just yesterday before the whole procedure, your sister had nice but relatively average boobs. Around a D-Cup you would have guessed. Now those D-Cups looked more like two gigantic domes of flesh to you. Probably at least 48F-Cup you thought. Might be bigger though, not that you really knew bra sizes.
Your point of view was right in the center of her right boob. Her nipple to be precise. When you concentrated for a better look, you saw yourself. On a first look, you wouldn't have seen it. On a second look, you saw eyes, a tiny tiny nose and a little mouth on her nipple. Your nose being the tip of it. To the normal eye, it would just look like a slightly deformed breast-tip.
You were baffled, really.
"Bro can you stop staring at my boobs please? I know they are big, but common.", Serena blurted out, being all happy and laughing.
"You see, i'm not staring at the boobs, the boobs are staring at themsel..
...I mean the boobs are staring at me. No wait, I'm staring at myself.
That's what i wanted to say.", you stuttered.
Seeing you so visibly confused, your sister just started bursting into laughter.
"Aww man, you should see yourself down there" ~~Teeheehehee
"You know, I do see myself right there in the mirror.", you corrected her.
Serena, having tears of laughter running down her face, took a good minute to stop laughing.
"You know Tim, i'm really grateful for this. Even though I definitely will have to get used to you being my little nip.", she said, giving you a little "doop" afterwards.
Shrugging you said, "Whatever, just get used to it. I will need some time to process this as well. But Dad is just nowhere to be seen huh."
"Well That's exactly what he wanted right? I wonder if he's able to hear us?", Serena wondered. "Hey Dad you in there?", your sis called out, tipping into her left boob.
"oh well he's probably still asleep," she figured. "Anyway, let's go back to bed, it's still way too early for me".
She covered you with her hand and went back into her hospital room.
Once Serena and her little boob-family stepped into her room, two things happened.
First, she got hit by a pretty cold breeze from the open window which a nurse must have opened.
Second, you felt an odd sensation. The cold gust from the wind caused you to harden, like any working nipple would. You found it difficult to speak, or moving your eyes. When Serena noticed this, she just blushed and hopped into bed again.
"Well that felt weird", you stated from under the covers.
"I guess you will have to get used to that too. My nipples can be really sensitive at times".
Getting that info, you tried not to think of the other occasions your sisters nipples might get hard.
"We should put up some rules for all of this", your sis stated. "Firstly, what happens, happens. We will be spending the whole next month like this, so it's kind of programmed that at some time, something stupid will happen".
You agreed to that rule, not that you would have any other choice.
"Secondly, we won't tell anyone about this", she said.
"Yeah i would like it that way, too. Imagine all the stupid jokes we would get if this comes out", you agreed.
"I also would like to add one rule", you said. "Can you please at least try to address me as a human being? I think it would really mess with my self-awareness if you just think of me as a nipple."
"Yeah I get that. Alright any other rules?", Serena nodded.
"I think that about covers it", you concluded.
After settling the rules, you both just went back to sleep. You noticed her breath getting more calm and her heartbeat slowing down.
To you, that was like someone singing a lullaby to you, so it took not long for you to drift into slumber as well.
....