Next Day

At noon, I studied the Doctor's Notebook. Among all the notes about different treatments; there was a serum that made the taker have a higher sensitivity for a certain number of hours. Depending on the dose, of course. "Hmm..."

My mind spun with possibles.... I hadn't been able to use the MRI Machine yet; and if I used the Serum I could make Becky agree to letting me touch her and use the machine to figure out what's wrong. With that in my head, I check on what Becky was doing. A quick peek into her room, I saw she had been reading more of the book she had brought with her. But she had fallen into a small doze.

Perfect.

I rush down to the Medical Room, and grabbed a desovlisble blow dart before filling it with the serum. After loading it into a Blow Gun, I sneak back up and aim at Becky's shoulder...I blew the Blow Gun and it hit the target!

She gave a slight hiss and slapped the spot before rubbing it. "Oww...what was that?"

I smirk, then hide the Blow Gun before going into her room. "Hey, you doing ok?"

She turned over, and gave a smile. "Hi. Fine, but I think I tweaked a nerve or something."

"Really?" I pause a minute. The Serum wouldn't kick in for a minute; and from the dosage I gave her...it'd be active until almost dinner. So I'd have to buy some time. "Hey, do you remember when Mom used to help us learn how to brush our teeth?"

"Yes, I do. Why?"

"I was wondering...if you could help me practice for when I have 'kids'."

Becky sat up, "How can I help exactly?"

"Well..."

"'Well' what-? Oh no, you're not going to brush my teeth!"

"Please, Becky? Just once?" I beg. "For old times sake?"

She started to say something, but then caved. "Fine. Fine....but only this time."

I nod and hurried to the bathroom, to grab her toothbrush and put toothpaste on it. I have Becky sit in the chair that was in the room, and then came up beside her. "Say 'ahh~'."

Becky opened her mouth. "Ahh~"

I start brushing her teeth; starting with the back and slowly working around. After two minutes, Becky started to grip the arms of the chair. I move on to her tongue and start scrubbing that clean...

My sister started to moan, and her eyes clouded with pleasure from the sensation of having her tongue scrubbed clean.

The Serum was working!

I stopped saying I was finished, and Becky rinsed her mouth before swaying on her feet. "You feel alright, Bec?"

"I...I'm not sure....my body feels odd..." She started to fall forward and I grab her.

"Let me take you to Medical Room." I say. "At least there we'll have medicine in case you get a fever or something."

"Y-Yea...let's...let's do that."

Carefully, I lead my sister to the room and lie her down on the table before saying I'd take her temperature and listen to her heart. She didn't protest, and stayed still while I did. I report that her temperature was a bit high, but her heart beats were good.

"Maybe you've caught a bug? It's possible." I suggest.

Becky starts to pant. "It's so...so hot in here."

"No, it's cold. I think your fever's risen...I'll get you a paper gown that's down here. Maybe that'll help cool you down?"

She hesitates a minute but then agrees, before shedding her top and pants. Once she's in the gown I see a wet spot on her underwear; perfect! I tell Becky that we could use the MRI Machine to see if there was something wrong...she reluctantly agreed. The Machine was portable so I rolled it over to the table and positioned it over my sister; with this model you didn't need to inject any dye into the patient. Turning it on, I took a picture of every part of my sister's body.

We looked through them, and saw nothing wrong. I say we should try to get her cooled down a bit, then I mentioned that her underwear was wet. Her face flushed darker, "Wha-What do you mean?"

"I think...you may be trying to have an orgasm, Beck."

"Certainly no-"

"Becky!" I shout. "You are, but I think you're trying not to. And that's dangerous...at least let me help you."

"But-But we're siblings! We can't do those kinds of-"

"****."

She finally gave in and, as she was too tired and somewhat-limp, I put her feet in the stirrups after removing her underwear. Her woman hood was flushed and I adorned gloves after turning on the big over head light. I examined her outer lips, and then spread them to examine the hole...before inserting three fingers. After all those days of strechting her out, she took my fingers easily.

"That's...working..." She panted.

I remove my fingers and open the drawer that had all the Didlo's. Picking up one that was large, long and had a vibrator inside it, I bring it back to my sister and insert it. She let out a gasp when the tip touched her the entrance to her womb, and a shriek when I turned it on.

"Ooooh!...ah!...ha!...Mike, what's-"

"It's just a Dildo, Becky. Relax." I put a towel under her just in case. She starts to writhe hard on the table, and I tell her to stop or she'd fall off. When she didn't I hold her arms above her head, and say, "It's ok, Becky. It'll be over soon I'm sure."

She soon cummed; a large splash actually. Good thing I put a towel down, and I remove the device before cleaning it. My sister was still panting and I take her feet from the stirrups, before making the table put her in an up-right position. She drank some water while I listened to her heartbeat again, and felt around inside her with my fingers.

Becky was cooling down now, and a quick glance at the clock told me that two hours had passed since I hit her with the dart. Almost dinner time.

"Everything seems ok. You shouldn't hold back like that again, Bec."

"I won't." She swears. I help her up to the Living room and lay her on the Divan; she looked so perfect.

I clear my throat. "Hey uh, Becky?"

"Hm?"

"I'm not real hungry, so we don't need to worry about dinner."

"...'kay."

I pause before adding, "I'm thinking of becoming a Doctor...a private one."

"I can see you doing that."

I smirk, and then put a pillow behind Becky's head and another towel under her...just in case. I leave her to recover while I cleaned up the Medical/Examination room. And to put the MRI pictures onto my phone. When I got back, Becky had fallen asleep. Carefully, snap a few more pictures with my phone of her naked body. Then covered her with a blanket, and let her sleep.