"I need to piss!" Katherine shouted.

"Well go ahead and pee." Her Dad said back. "I just got in here so I'm not getting out."

"Fine." She pulled her bikini bottom down and sat on the toilet. The sound of her pee filled the room. Her shirt was soaked through from her run earlier and she looked over to the curtain and then pulled in off over her shoulders and dropped it on the ground. "Oh, that felt good." She said, still sitting on the toilet. "Does Mom have any shirts in the bedroom? I need to change."

"Sure. Just take a look." Her Dad said and then pulled the shower curtain over to talk to his daughter.

"Oh. Looks like we're both naked." He said, blushing and starting to chuckle. Now relaxed, Katherine smiled and started laughing with him. They were a liberal family and saw each other naked around the house a lot. So given that she was hot and feeling good after her pee, she didn't even bother covering up.

"You are pretty sweaty. Do you want to take a shower after I get out? There's a towel on the door."

"Yeah. That's a good idea." She said getting up and flushing the toilet.

"Can you first grab me a beer from the kitchen, though?"

"You want it in there?"

"Yes. That's what I said, Katherine."

"Fine." She washed her hands and kicked off her bikini bottoms and walked through the house naked to the kitchen. She got a beer out of the fridge, opened it and took a big swig before going back into the bathroom and shuting the door. Her father had not bothered to close the curtain and was scrubbing his face with soap so he didn't notice that his 25 year old daughter could see his semi erect penis hanging in the streaming water. She felt a tingle in her legs. He had obviously gotten hard when he saw her naked on the toilet, and though it made her feel kind of horrible, it was causing her to get a touch wet.

"Here's your beer."

He looked up and noticed she was standing right next to the curtain, the beer held out just above his newly hardening penis. He grabbed the bottle and just stared at his daughter. He was now fully erect and she was staring right at it. He blushed again and took a swig.

"Looks like someone's having a nice shower." She said, still gazing at her father's prick.

"Well. Sorry about that, but it's natural. You know that. No big deal." He took a big swig, finished the beer and handed it back to Katherine. She set it down on the sink and sat back down on the toilet. "I'll wait for you to finish so you don't have to turn the water off."

"Okay, sweetie."

 Why had she said that? It's not hard to turn the faucet off. She knew she didn't want anything to happen with her own father but she was for some reason very excited about seeing how her Dad would maneuver around her out of the bathroom. Then the curtain opened. She stood. Her father stepped out of the shower and stood in front of her. He tried to slide past her but slipped and fell on her, slamming her into the wall. His penis stuck into her stomach as he tried to pull himself up, and the laughter started there, both laughing, both uncomfortable, embarrassed, and unmistakably turned on by the taboo of it all. Through their laughter, she reached down and stroked his penis trying to make it seem like a joke, but he let out a soft moan of pleasure and the laughter stopped. She stared into her  fathers eyes, something in her daring her to take it a step further. She put her hand back on his hard wet penis and stroked the full length of it. Once. Twice. Three times. Then once more. Then she pulled her hand away. He pushed himself off, tried to laugh and wrapped a towel around himself and left the bathroom.

She climbed into the shower, heard the door close behind her and immeadiately probed her aching pussy, now soaked from the sexual excitment of bolding stroking her father's penis. What had she been thinking? One stroke and maybe she could get away with it, but four strokes? That was clearly a sexual gesture and neither she not her father would be able to deny it when they met each other's eyes at her mother's birthday dinner later that evening. Would they be able to get through the dinner with out blushing or feeling horrible?

The drums were thacking away in her brother's bedroom below. She suddenly had an image of her father's prick pounding her pussy on her brother's bed downstairs. She fell into the fantasy and said aloud. "They're right upstairs, anyone could come in." Then she saw the door slowly opening. And her pussy exploded with two huge orgasms under the stream of shower water. She cried out loudly. Could her father hear in the next room? Probably. Did she care? For some reason, no.

They had managed to get through dinner without her mother noticing that her husbands penis was getting hard anytime Katherine met eyes with her father. And for Katherine's part, it was fun knowing that wool was being pulled over her mother's eyes. She was sure nothing more would happen, so forget about it. It happened. No use feeling terrible about it.

 When they got home her mother took her dad into the bedroom and shut the door. Katherine went to the bathroom and took a quick pee then went back into the hallway.

Oh yes. It was unmistakable. Her Dad had his cock inside her mother and she was moaning loud enough for anyone on the floor to know. Katherine felt wet again. Shit. She was gonna have to deal with this for a little while. She was sure it must be the beginning of some phase and that eventually it would pass but right now a small dribble of creamy secretion was rolling down her thigh. She had to get her hand in her pants. She unzipped them and shoved a hand inside her panties, finding a wet clit already bulging. She moved closer to the door. She could her him slapping her ass.

“Am I a bad girl, then?” Her mother asked. “Do you want to play that again, Mike?”

“Um...” Her father's voice broke. He was breathing heavy, obviously pumping hard. He slowed down a bit to ponder the question.

“It's okay, Mike. Wait. Stop.” Her mother scooted over on the bed. They stopped fucking. She took a deep breath. “Mike. It's okay. You are having a thing right now for her. It's natural. I'm okay with it. I think it's healthier to play out our fantasies a little than to suppress them. As long as it's always with me. I don't mind. I don't mind, honey.”

He took a deep breath and then in a small voice said. “Okay...” “I love you, Mike.” She said. “Now. Lay back.” Katherine could hear him lay down on the bed. “Good.” Her mother said. “Now. I'm going to tell you what she's doing to you, and while I say what she's doing, I'm going to do it to you. And you just imagine that it's her doing what I'm doing. Okay?” “Okay, Barb.” He said, voice still a bit shaky.

Katherine was very aroused. Her clit had risen and was aching to send some cum down her pussy as she listened to her parents most intimate conversation. “She's at the foot of the bed. She's rubbing your leg. Now she's rubbing your stomach.” Her mom said, her voice growing a bit husky. “She must be getting into it”, Katherine thought. “You told her you were sick and asked if she would rub your tummy.” “Yeah. Yeah. That's right. She's just rubbing my tummy.” her father whispered.

“Just the tummy. She's doing a good job. Making you relaxed. Looks like your penis is growing. She's making it grow, isn't she?” “Yes. She is. She is making it grow.” Katherine had never heard her father sound so vulnerable. Damn, that was sexy. “Now she's touching your penis.” her father groaned and she could hear the skin of his dick as her mother stroked it in her hand. “Yes. That's right. She's stroking your cock for you now. Katherine is stroking your nice big penis.”

Katherine's hand stopped and she gasped, covering her mouth with both hands. Had she heard correctly? Had her mother really said her name?

“Your sweet baby, Katie wants to suck your nice cock now.”

Oh. Shit. Yup. Her mother was definitely acting out her Dad's fantasy of fucking his daughter. But his daughter was her. Her mind was racing and her hand was back in her pants, rubbing her clit furiously. She was overwhelmed. Her Dad DID want to fuck her. Her mother KNEW. And more than that was actually helping him get off while thinking about it. Her head was literally spinning with erotic passion. When she heard her mom's mouth slurping and sucking on her father's cock, knowing what his erect cock looked like, having just held in her hand earlier that day, having actually stroked it herself, was too much for Katherine and she came hard. Her knees shaking, still trying to stand, her body quivering up to her head, she let out a loud moan as she felt cum gushing from her pussy. Then again, another spasm and another moan. Then she fell to the ground.

Her mother was still sucking, she could hear it, but it was slower and much quieter. Had they heard her? She was just outside the door. She needed to get out of there. She pulled her pants up and run down he hallway, into he room, closed the door and flopped on her bed, trying to catch her breath.

What had she just done?

“Oh my God.” She thought. “I hope they didn't hear me, but that was the best cum of my life. I will cum again just thinking about that cum.”

Was she crazy? Fucked up? She was too alive too care at the moment. Her hands were wandering down to her pussy again. She needed to make it gush hard on her bed. Maybe more than once. Then she would think about who she was turning into. Right now all she wanted was the hot fat cock of her father inside her warm wet cunt.