All persons in this story are 18 years of age or older.
*****
As I was pounding Marie from behind, with Bree right next to us watching her brother's cock disappear into her sister's pussy, I was already thinking about what Bree and I had agreed upon yesterday. Namely that after I blew my load here during our morning escapade, I would stay and piss in the bushes for Bree to watch. It might have seemed like an odd request for her to make, but the three of us were slowly upping the ante of how to excite each other more and more over time.
Marie was grunting with each thrust, as was I, and Bree was fingering her pussy as she watched. She busted her nut first, crying out as a signal for us to notice her despite our frenzied movements. It was kind of an unwritten rule that whenever one of us came, the other two watched carefully. It aroused us to see our siblings climaxing, and it was respectful of sorts to acknowledge their pleasure. The whole point of doing all this together was to be watched, after all.
Marie licked her lips as she watched Bree's fingers leave her sopping wet hole. She was getting more and more accepting of interacting sexually with her sister rather than just me. I suspected she was bisexual, rather than how Bree was just willing to do anything and everything sexual. Seeing the look on her face as she stared at the perfectly trimmed vagina near her face got me off hard, and I started to cum.
Normally, I would have been upset somewhat that I came before the sister I was fucking, but by this point we each had a mutual understanding that all of us would cum one way or another before the escapade ended. If my cock didn't get her off, my mouth or Bree's fingers would. I yanked my penis from her clenching flesh sleeve and aimed it upward, then felt the familiar tingling pleasure spike up through my shaft before my semen released in torrents across her back. I grunted on the second, more powerful spurt, and it sailed all the way up to her neck. Since she was already sweaty from her run, the excessive cum smears on her skin and sports bra wouldn't really bother her.
"God, yes!" Marie exclaimed in a breathless, well-fucked sigh. "You always cum so much!"
Bree was already snaking her way under her sister and moving to finish the job I couldn't last long enough to complete. Marie purred as she felt her sister's tongue slip between her swollen pussy lips and find her clit. I watched with a dripping boner as Bree ate Marie's pussy not more than two feet from where I stood. Marie grabbed Bree's hair and mashed her face into her cunt, her mouth slack and hanging open as she enjoyed the impending orgasm that was building in her.
When she burst finally, Bree moaned and sucked it all in. She had told me many escapades ago that Marie especially liked when she tongued her piss hole. It was so naughty, like everything we did together, and it excited me to know that. I rarely got to eat Marie's pussy, though Bree practically sat on my face every night. To be fair to her though, she usually prefered for me to eat her ass out instead.
Marie climaxed, and hard, and I felt the sensation to piss starting to build. Bree wanted me to surprise Marie by pissing as close to her face as possible without actually getting any of it on her. We weren't trying to be gross, just kinky. I jerked my cock absently as I waited. Marie really enjoyed herself on Bree's mouth, and took her time before withdrawing her slick crotch. Her pussy was shining with saliva and cunt cream.
Bree's face was covered in both as well, but she didn't forget our agreement. She glanced at me and nodded, then at my dick in anticipation. Marie happened to look over at me just as I let loose, and her eyes widened a bit when she saw that I was pissing close to her. I kind of expected her to be shocked and maybe grossed out, but instead of leaping away she just stepped slightly to the side and turned to fully face me. Her eyes were on my dick and the stream of piss arcing out of it.
She didn't say anything the entire time I urinated, but she did seem very interested in it. There was only the sound of my piss hitting the wood chips that surrounded our bushes behind the shed. I could tell Bree was happy with this result, judging from her smile as she licked her sister's pussy juice from her face.
I finished and shook the last few drops before tucking her cock back into my shorts. Marie smiled up at me.
"What brought that on?" she asked me.
I shrugged. "I just thought you might be excited by it. Bree was."
We both looked at Bree, who was nodding. "If I had to go, I'd piss for you both too."
Marie chuckled. "Why are you both into pissing all of a sudden?"
"We're into being naughty with each other," Bree explained. "You like your piss hole licked, how is that different?"
Marie blushed. "I guess it's not that different. But it is different."
We laughed it off and cleaned each other up. By now we had a routine for this. Marie's clothes didn't need to be cleaned really, since they were already sweaty. But we did need to wipe the cum from her back. We intentionally never restricted where my cum went, since that would detract from the heat of the moment. Both sisters were very clear that they wanted me to cum wherever I felt like cumming. I had painted their faces, their bodies inside and out and in all holes, and at this point I let my dick decide where it wanted to spew. Marie probably expected me to fill her tight pussy earlier, but she was equally enthralled to feel me spray her down instead.
Bree used the hose to fill her hands with water so she could wash the vaginal fluid from her face. I didn't need any cleaning, in fact I loved purposely leaving their pussy juice on my dick. It was so hot to know that wherever I was out in public, I had the forbidden fluid of incestuous copulation in my pants.
Later that night we watched a movie as a family. Mom and Dad were cuddling on the couch, while the three of us kids sat separately around the floor. We were all very careful not to touch each other around our parents. Not only would it be suspicious, it would also ruin the fun of keeping our trysts a secret. Marie's tendency towards exhibitionism had never blossomed beyond fucking behind the shed, thankfully.
After the movie our parents went to bed, per their usual routine. They were fond of leaving us kids to ourselves in the basement while they retired to the quiet upstairs. It worked perfectly in our favor. We could hear their footsteps creaking on the floor if they ever came downstairs, so we weren't worried about being caught. We could even grunt and groan at full volume and not be heard by them. We had tested that thoroughly, by having Marie stay upstairs in her room, with the door open just in case Mom and Dad happened to do that, while I fucked Bree's ass hard in the basement. Marie ended up coming downstairs after a few minutes because she couldn't hear anything and wondered if we had even started.
So we were pretty safe down there. Marie though, being the older and more careful one of the three, seemed to enjoy coming up with rules to keep our fun a secret. She insisted that we still keep ourselves as quiet as the moment would allow, and to always wait until we heard the toilet flush before getting naked, since that was the last thing that we could hear before our parents went to sleep. Bree and I let her be in charge, so to speak, since she had good ideas and always rewarded our cooperation heavily.
When we were finally ready to play, we peeled our clothes off and scooted close together on the floor. By this point, we were all experienced enough with each other that we weren't exactly like horny teenagers experimenting for the first time. We had developed a nice pattern of getting ourselves aroused sufficiently first before diving into sex. This usually meant a double blowjob for me, which I knew would spoil me for regular non-threesome sex, and my sisters lezzing out with each other. I would eat pussy and ass too, but I couldn't do it for both of them at the same time. It just usually worked out that they would focus on each other mostly. I didn't feel left out at all, in fact I loved watching them.
Tonight their double blowjob seemed to be purposely slow, very much a tease with the tip of their tongue or their lips only softly kissing my balls. I wasn't going to complain, but I could tell they were doing something on purpose. In fact, Bree seemed to be sliding down low and trying to move my legs.
"What are you doing?" I finally asked her.
Marie took my entire length into her throat right then, distracting me while Bree pushed my legs apart further than they were.
"Relax," Bree replied. "You're getting your ass licked tonight, bro."
I smiled, knowing that she was dying to do this from earlier conversations. Many times when we weren't busy fucking each other we would have open sexual conversations and share our deepest and even darkest fantasies. We didn't judge each other, no matter how illegal our fantasies were. Our current situation was technically illegal, after all.