Yes

I let Becky rest a bit, as I clean up everything. After a few moments of replaying the events in my head...I was hard again. Lord this was going to drive me crazy!

Grabbing the bag of supplies; I find Becky on the Master Bed in an over sized T-Shirt. She was a bit tired, but okay. I wanted to see Becky as Fish Girl again; to run my hand over her smooth scales...feel her warm insides wrap around my shaft...

The urge was strong and hot, and part of me wondered if I was going insane. "Just ask her, can't hurt." I cleared my throat. "Bec?"

"Hmm?"

"Wanna...be a fish again?"

She shook her head. "We just-"

"Not now, later."

"...I suppose."

I took that as a yes, and give her aspirin to help with the pain later. I left Becky to rest, and read more of the doctor's journal. It told of many different experiments he had done...each more amazing than the next.

Becky came down still in the old T-Shirt, and started to make lunch. I come up beside her, and we make small talk. Once we had eaten; my sister went back upstairs to rest more. I follow with a small can of knock out gas in my pocket. When we neared her room, I sprayed the air and she unknowingly walked into the cloud. She wouldn't be out for long through, I had to hurry.

I take her back into the Master Bedroom, and make her swallow the Hypnosis Pills. She slowly comes around, and I whisper in her ear, "Time for round two, just like you wanted. Sad to hear you're not well, 'Mermaid'. Pity ."

"Ye-Yes...same here."

"Shall we begin?"

"I'm ready, Doctor."

I hand her the pills to make her an Aquatic again, and lead her to the bathroom. I filled the tub with water, before having her sit inside. I do her vitals once more, then probe her mouth with my fingers. Gently I pull her cheeks a bit...stretching them. It would take a few days, but then her mouth would be able to take large objects. "Open wide....wider, Becky...tilt your head back....tongue out, all the way....good." I look inside and marvel at my sister's beautiful mouth. "Hmm...I see. Cough."

*Cough*

"Again."

*Cough, Cough*

I grope her breast with one hand. She moans, and I tell her to close her mouth. "Seems slightly red, 'Mermaid'. Come lay on the towel here...that's right....legs apart....farther..." I finger her folds, finding them warm which makes my shaft harder than ever. "No lumps...clench your muscles...good girl...again....very well done." I open her again, and probe the entrance to her womb. "Looks good in here, seems the problem is in your throat."

She sits back in the tub, and I tell her my speical medicine will help her get better. "You trust me right? You do as I say."

"I do, I'll do as you say."

I reveal my shaft, hard and aching. "Say 'ah'."

Becky opens her mouth. "Ah~"

My shaft goes into her oral cavity, and soon we have a rhythm going. Becky's throat pulls me deeper down and I shot into her stomach. But I kept going; saying she needed multiple doses.

"That's it 'mermaid'...swallow it all...obey the doctor..."

After four more times, I'm semi-dry. A glance at Becky's stomach and I see it's a tad swollen, from all my seed inside it. She pants, and doesn't object when I rub her belly before taking her anally. When that finished, she became normal again. I say in her ear to get dried off, and go to bed. When she would wake up in the morning, Becky wouldn't remember a thing.

But that didn't mean she wasn't going to be 'deeply' examined tomorrow...