“So how did you and my brother meet anyways?” Amy asked while laying down on her bed. 

She placed Katie on her chest just above her boobs.

“Well besides him running into my ass at school, we met because of Dianne. I was with Miss Kenny before Dianne stole me away. Dianne then used me to get Max out from her womb. I guess he got stuck in there somehow.” Katie explained. 

“Oh wow that’s quite a story. Probably don’t want to tell too many people that you guys met inside Dianne’s vagina” Amy joked. 

“Yeah and that Max jizzed all over my face and boobs.” Katie said laughing and then she remembered that Amy is Max’s brother, “Sorry probably TMI.” She apologised. 

“No worries. Max and I aren’t really normal siblings. We shared everything growing up which made us super close. And I know, he’s a bit of a pervert, but I still love him. Did you know I once walked in on him jacking off into a sock?” Amy said.

“That is hilarious! I’m so going to hold that over him some day.” Katie laughed.

“That’s not fair, that was two years ago.” I said to myself while eavesdropping. 

“You both have been through quite a bit. I’m glad you’re here now so I can keep you guys safe.” Amy said sincerely.

“Yeah it wasn’t all bad tho… We seem to have some kind of sexual experience once or twice a day. And man is it ever better than normal sex. Would you agree from your giantess perspective?” She asked.

“Yeah there is something special about it... Girl to girl talk, forgetting about incest, Max seems to have a superpower to giving amazing orgasms. I don’t think it’s only his size, I think he just knows where to go and touch.” Amy admitted.

“I haven’t experienced all of him inside me, but I can second that he knows where the clit is. But honestly, there is also something about having a giantess’ tongue eat you out too. All the bumps feel amazing on the naked body.” Katie said while climbing up onto Amy’s chin.

I was getting really turned on by their conversation. Listening to both of them talk about me and having orgasms, it was really hot. Hearing how much Amy loved it, I got a strong urge to give her an even bigger one. I placed my hands against her lips and could feel how hot and sticky they were. She was getting wet just from talking about me. 

“I’ve only had a tiny down there, I’ve never had one in my mouth before.” Amy admitted feeling tingly sensations by her vagina. 

“You have a beautiful mouth, I bet you’d be good at it. Wow your lips are so plump and squishy.” Katie said admiring Amy’s features and sitting on her bottom lip.

I massaged the outside of Amy’s vagina, only growing exponentially hornier. I couldn’t believe that I was going through with this. All my life I was told incest was wrong and now here I am, planning on giving my sister a massive orgasm with her unaware of my presence. Sweat dripped down from my forehead as I still continued on with it. I had never been harder before. My dick throbbed and pulsated like it could blow at any moment. It felt like I hadn’t masturbated in a month and the urge to climax was killing me. I slid my hands in between her moist flesh and found her clit.

Amy tightened her teeth to hold back from moaning. Her cherry lips parted in the process and Katie fell in between them. She kept her teeth closed so Katie could stand on them without falling into her mouth. 

“I’m not gonna lie, I am very turned on right now… And without Max being here, this might be the best time for us to experiment. Like you do me then I do you deal.” Katie said caressing the inside of Amy’s lips.

At this point, Amy couldn’t say no. She was dying trying to not burst out and moan. She slid her tongue in between her teeth and once she felt Katie, she pushed the tiny girl into the underside of her lip. 

“I’m gonna do me too so don’t mind my moaning.” Amy said finally releasing some of the pleasure that had built up. 

My sister was pleasuring my girlfriend, while I was pleasuring her. I couldn’t help but think for a second, just how fucked up this whole situation was. I played on Amy’s clit like it was a crystal ball and now I could feel her body moving in conjunction. Suddenly, my back was met with Amy’s giant finger as she pressed it against me. My first thought was that I was caught. But then to my surprise, she pulled up on her panties, giving herself a camel toe. The fabric pushed my whole body into her wet flesh, right where she wanted me. My sister knew that I was down here, but she wanted more. That was my go ahead to give her my all. 

Amy played with Katie in her mouth, moving her from cheek to cheek, licking the tiny body from head to toe. She was surprised by how much she could feel of Katie’s body. She could feel her boobs jiggle from the flick of her tongue. Eventually she had to speed things up, Amy was getting close to climax and she wanted to do the same for Katie. She stuck the girl to the roof canal of her mouth and then made circles with her tongue, grazing every inch of Katie’s body. Katie began orgasming from the intense pleasure that Amy was creating. 

Amy pulled up on her panties until they were close to ripping. I was forced hard into her lips where I used her juices to hump her wet skin. However, it wasn’t enough for my sister, she craved more. With a final sporadic move, she slipped her finger down and drove me inside her pulsating pussy. Her finger scooped me and then rubbed me into her g-spot. My naked body slid up and down, engulfing both of us in pure ecstasy. My dick was met with her amazing wet internal flesh and I couldn’t hold back anymore. Pleasure consumed my body as I released buckets of my load inside her. Amy also orgasmed and her whole body arched and tightened. She nearly swallowed Katie in all the excitement. She could taste that Max’s girlfriend enjoyed herself too. After a few minutes of resting, Amy plucked Katie from her mouth and set her on the pillow. 

“I’m gonna need a breather before I do you.” Katie explained. 

“It’s okay, I think I did myself too well to go again tonight.” Amy giggled still feeling goosebumps all over her body. 

“Well good for you girl, way to go for masturbation.” Katie laughed in return. 

“I’m gonna go use the washroom, I’ll be back.” Amy said getting up. 

When she got to the washroom, her opened up her underwear and looked for me. I was afraid to come out and face the reality of what had just happened. 

“Max? I know that was you, please come out.” My sister asked. 

I could feel her squeezing her vagina and trying to push me out. I was able to resist it but I decided to get out. She scooped me up on her finger and brought me over to the tap.

“I’m so sorry Max, please forgive me.” She begged while rinsing me off like she was erasing what had just happened. 

“No I’m sorry, I started it.” I apologised. 

We looked into each other’s eyes for a few seconds until we started quietly laughing. 

“I can’t believe we did that.” Amy said.

“I know, can we just put it behind us and pretend like it never happened. Just like the last time we had a 3-way.” I added. 

We both blushed and smiled. I was so happy that I could joke and move on without it being super awkward. My sister was amazing and I was glad to be back with her. 

“Okay so we’ll tell Katie I found you in the hall after you escaped mom’s room.” Amy said.

“Deal.” I replied.