So, Maryam and I were at the stop, getting ready to board the rail to downtown Sacramento, and she had her fingers down my pants for a moment. To be fair, I had my hand on her booty, so it was tit for tat, as it were. One would never know that we were brother and sister, albeit with benefits. Yeah, I regularly humped my sexy Arab sister, but wouldn’t you? We had the same father, but different mothers. Dad impregnated her mother while still very much married to Mom. Yeah, you do the math. Mom had a series of boyfriends over the years, so she wasn’t hurting, either.

“Oh, damn, I can’t wait to get you home today, bro, and slip this inside me!” Maryam whispered hungrily in my ear, stroking me just right to make it obvious what “this” meant.

“I wonder if your boyfriends ever have any idea how often you let your brother fuck you,” I whispered back to her, making her giggle.

“Does anyone know that you fuck both Mama and me? You can’t resist Arab girls, can you? You love our olive skin!” Maryam teased me some more as we boarded the train at last.

“Well, as you said, I’m fond of Arab girls,” I shrugged as Maryam licked her lips.

“It’s cool. I often spread her thighs and buns after you’ve fucked her silly and tongue her to another orgasm. By the way, I love how her ass tastes when you’ve come inside her backdoor. Maybe I should invite her to join us and rim me, too,” Maryam answered me huskily, her lust undeniable as she let me grope her under her skirt.

“She should. You’re delicious!” I slapped my sister’s butt and pinched her left cheek.

Right then, another hand wandered over to Maryam’s tush and started caressing her buttocks. Instead of complaining, my sister lifted her skirt just enough to invite the owner to play with her plump bottom a little more. A second, roaming hand began pushing toward her twat, sliding her panties aside to toy with her clit and her folds. Far from resisting this, Maryam raised her skirt some more and slid her panties down her thighs to assist this new third party. The owner of those hands now overtly played with her pussy, much to her gratification.

“Oh, damn! Don’t quit now ... please don’t!” Maryam begged me, afraid that I’d suddenly leave her entirely in the hands of our new companion.

Rather than quitting, of course, I was just about to make things worse for Maryam by moving my hand up her blouse to free her breasts from her bra. This was when I realized that she wasn’t wearing a bra in the least. Grinning, I lifted my sister’s top all the way to her shoulders and she simply pulled it off, leaving herself completely topless. Our new partner was now joined by another person, who had his or her hands on her tits, fondling her with obvious pleasure in the act.

“I think that we have some company, sis,” I said the obvious.

Maryam just laughed as she welcomed my hands back onto her ass. It wasn’t much longer before my fingers rubbing the outside of her puckered ring made her bite her bottom lip. At the same time, another passenger put a mound of her breast into his mouth, and yes, it was a man. The passenger playing with her twat was an older, married man, whereas a younger guy had her other breast in hand. Now, of course, yet another person began kissing Maryam’s mouth and even her neck, this one being a thirty something Latina in a pantsuit with her dirty blonde hair in a bun.

It didn’t take long for Maryam to free her latest partner from her bun and unbutton her blouse. I was so hard, it wasn’t very long before I liberated my cock and balls to dry hump my sister, running my dick along her butt crack. My hands caressed her cheeks as I did this, even as the older man now fingered her cunt and brought her closer to release. I dry humped Maryam for a little while longer until I heard the Latina clear her throat.

“Hey, papi, I know that she’s yours, that’s obvious, but others want a turn at her sweet ass, too. Here, let me service you while our companions get a little quality time with that fine booty,” she told me, kneeling to suck me with brazen lust in her eyes.

This was when I noticed her wedding band and she winked at me, adding, “Yes, I’m married. My husband is the one fingering your girlfriend. Yep, he’s an older man, but he’s a great guy.”

“The couple that plays together ... Great minds think alike. Our parents are like that, too. Dad has been married to Mom for many years and has bedded Maryam’s mother for much of that time, too. Yes, we’re brother and sister as well as lovers. We encourage each other’s activities, as you can see, taking pleasure in it,” I groaned as I felt my new lover’s lips and tongue bathe my prick with her spit.

“Yeah, that’s the wave of the future, I believe, and that’s also the point of this train. You’re not on just any train. It’s an experimental train where it’s not only legal, but preferred for people to fuck their way to their destination. It’s not even unofficial. If you’ll look at the policy signs, you’ll notice messages urging people to get it on with each other. By the way, your sister’s ass tastes great on your cock! I’m Lucinda. Oh, look, Gary, that’s my husband, is fucking your sister now and his buddy Matt is licking her booty like a sundae!” the woman announced, and sure enough, her hubby shared her with yet another guy.

Sure enough, the train started to become a mass of naked, sweaty, tangled bodies that carried us all away. Our clothes didn’t last much longer and I found myself balls deep inside Lucinda, fucking her sweet twat and kissing her shoulders as I took her from behind. Far from objecting to this, my new, happily married lover pushed back at me on each stroke with an enthusiasm that couldn’t be counterfeit. Her Spanish profanities added to the clear effect of a truly ardent and hungry companion, determined to enjoy herself and service me as well.