Elizabeth begins to lose control

As she stood in her bedroom and primped her long blonde pigtails, Elizabeth's internal voice piped up that maybe this whole thing was going a little far. In the past month, she'd gone from sleeping at Megan's house once in the first week, to practically living here full time. She hadn't seen Jeff in over a week, and they now mostly communicated through emojis and 'sexting' which she didn't realize was a thing until she saw an article about it on social media.

Maybe it was the fact that she now thought of her little sister more as 'Ms. Hastings' than as Megan now.

Maybe it was the fact that she found herself wearing tartan skirts, pink tshirts, and floral patterned denim miniskirts, 7 days a week. Her closet had started to look like an oversexed schoolgirl's.

Maybe it was the fact that after she continually forgot to clean the house during the day, her sister had started to simply asked her to take out the trash and clean her room.

No, she knew what was really bothering her inside. Last night, while they were having sex on what she now thought of as Jeff's bed, Jeff had been holding her pigtails like handlebars and pounding into her from behind, bringing her to the crest of a delicious orgasm, when he'd slipped and called her Lizzie.

She came so hard she'd passed out.

She didn't know what disturbed her more about that: she'd instantly turned into a ball of electricity surrounding his cock at being called Lizzie by her husband, or that he'd immediately cum as well, and then repeated in her ear over and over as she faded to black "I love you Lizzie-bear."

Just thinking about it now, she was getting wet all over again. What was this whole situation doing to her? Was it awakening some secret desire, secret fetish that she didn't realize she had? Did she deep down, want to be treated like an airhead teenager who wasn't anything but a good fuck?

I have to stop this, she resolved. I have to stop this before it goes any further and I do something I can't undo.

Jeff had left early that morning, and Elizabeth was alone in the house. She noticed it was already past her normal time to leave for work, and panicked. She was going to be late for work and Ms Hastings would be angry with her. She threw on her pink tartan mini, tight midriff baring white polo, and pulled on her white knee high stockings and black heeled mary janes, and raced out the door. She'd forgotten to put on her underwear in her hurry to get out, but she reasoned it was more important to be on time than anything else.

Elizabeth turned her key in the lock at Ms Hastings front door and let herself in. She could hear Ms Hastings in the home office, loudly yelling about something on the telephone, but she was so rushed that she didn't pay any attention.

She called out "Hey Missus H, I'm like, back!" and darted into her room. She had been practicing her airhead valley girl slang, and knew she sounded like an uneducated bimbo, but reasoned to herself that it was a part she had to play if no one was to find out that she was really Ms. Hastings' older sister. Today she was supposed to clean her bathroom, which was always disgusting.

Ms Hastings met her in the living room as she was getting set up. "Lizzie, what is the meaning of this?" she spat.

Elizabeth rolled her eyes, "what now? I didn't do shit."

Ms. Hastings huffed. "You were supposed to come home last night. Now you come home dressed in the same clothes and smelling like sex! I know you were sleeping with Jeff again. We've discussed this and as long as you are living in my house, you will obey my rules. You are not allowed to stay out overnight without permission. You have to be punished, girl."

Elizabeth grabbed the short hem of her skirt and tried to tug it down, looking at her sister's feet. She felt shame at having disobeyed her little sister, something that felt strange and natural at time same time.

As Ms Hastings stormed over, Elizabeth noticed her sister was wearing very high heels. They made her legs look very attractive.

"I... I'm like super sorry, ma'am."

"Your diction has gotten atrocious too." Ms Hastings said, knowing full well that it was she who instructed Elizabeth to speak like this. "You have a choice, girl. You can be punished here and now, or I can take it out of your allowance. Choose quickly."

Elizabeth's mind raced. "I, I guess like, now. I like, super duper need my allowance."

Ms. Hastings nodded curtly and sat down in a wooden chair in the corner of the living room, and motioned for Elizabeth to follow her. As soon as she was in reach, Ms. Hastings grabbed one of her pigtails and bent her over her lap. Elizabeth flailed, "Like, what are you gonna do to me?" She cried.

Without further explanation, Elizabeth felt her sister flip up her skirt and felt a hard "SLAP" on her exposed ass. "Ow! Like sorry, I'm super sorry!" she cried out in pain.

"5 spankings for staying overnight at a boy's house, another 5 for not wearing panties, you disgusting little skank." her younger sister ordered.

SLAP!

SLAP!

SLAP, SLAP SLAP!

With each spanking, Elizabeth felt the final little pieces of her dignity and self respect crumble to dust.

SLAP!

SLAP!

She ceased wiggling and resisting in her sister's lap, any resolve to resist mometarily gone. She felt she deserved this now. She felt that she needed to be punished for disobeying her big sister.

She felt wet.

SLAP!

SLAP!

Her sister's hand had stopped spanking her, and had rested itself on her red and stinging ass. She shuddered a little, and felt her special phone buzzing with messages in her pocket, where it pressed between her sister's lap and her hip.

She waited there, for instructions to get up, when she felt the hand on her ass move down between her shaved thighs to her hairless wet slit. She moaned quietly as a single finger rubbed up and down, gently caressing her pussy as the pain from the spanking her big sister had just given her began to fade.

"Are you going to obey me next time, girl?" Ms Hastings asked, a note of hesitancy in her voice.

Elizabeth couldn't comprehend what was happening, but managed to moan out "Yessssss"

Her sister kept rubbing, gently. "Tell me the truth girl, did you forget your panties on purpose? Was this just a ploy to entice me? Things lately have gotten confusing, I know you've been trying to... do something to me."

Elizabeth was sure she didn't know what her big sister was talking about, "No, Ms Hastings, I don't like, know what the fuck you're talking about."

Elizabeth felt her mind let go a little more as her big sister entered her with one tapered finger. "You sure you didn't want this? Do you want me to stop?"

Elizabeth moaned again, shuddering on her sister's lap. "No, like, don't stop!"

Ms Hastings smiled and rubbed at her g-spot and clit. "Tell me what you are then, girl. Are you my older sister? Or are you just Lizzie, my airheaded step-daughter slut?"

Elizabeth struggled to answer. Her mind felt like a hurricane, and she felt the need to resist, if only to keep some small bit of sanity and sense of her real self. Until nkw, she had just been pretending that Ms Hastings was her big sister. Step-mom was a new world entirely. She felt another finger enter her and knew something was breaking. Something that wouldn't be fixable.

"I...."

A knock on the door interrupted the spell.

"I.... need to get that, Missus H." Elizabeth finally gurgled out.

"Oh, yes, quite. I need to get to work too. Get up girl, see to it and don't spend the night without permission again." Ms Hastings ordered.

Elizabeth shuddered as she walked to the door, smelling like sex and sweat. She didn't know what happened, but she knew she'd kept what was left of herself. Why was she falling into this strange situation? Was she really about to let her younger sister finger fuck her after giving her a spanking? How could she even accept a spanking, let alone the incestual act she was letting her Sister-step-mom perform on her?