This story has been edited by Demiruging, I want to thank them for their help.
***
It was the second evening of Brian Parker's training for a swingers weekend at the Brooks Hotel that his wife Claire Parker had arranged with another couple called Frank and Maggie, also known by their avatar name 'Suger-spicy2' on an adult friendship and dating web site. It was about eight in the evening, and Brain was stripping off his clothes in the second bedroom of the house. Claire his wife was already dressed in black stockings and a black suspender corset. Her pert breasts were loose and proudly free, and she wore black ankle boots. She was also attaching a medium-sized pink dildo onto the strap-on harness she was wearing. Brian's training was for him to be pimped out as a sex slave and to be fucked with a strap-on up his anal back passage by his wife and another swinger's wife called Maggie.
"Hurry up I want you on your knees quickly please Brian," Claire told him.
"Ok, ok. I am doing it, see I am getting down now." Brian said back at her.
Claire took a riding crop from a shelf and smacked Brain's bare bottom with it, not so hard it would leave a mark but hard enough for him to feel it.
"You need to learn some basic manners Brian or you'll not going to enjoy this very much!" Claire told him.
"I am sorry Claire but this is going a bit further than I am wanting it to. I find it humiliating to train like this." Brian complained to her.
She smacked him again on his bare bottom.
"Let's get something straight Brian. I have let you enjoy yourself and indulge your sexual desires fantasies for far too long. I am now 'Your Mistress'. Of this house and everything in it, and that includes you, Brian! Do you understand?" Claire rebuked him for answering back and being slow to show the proper respect to her.
She put down the crop and smeared gel all over the pink dildo and then took position behind Brian and began to slowly work the lubricated tip of the pink dildo into his anal sphincter and pushed it into his anal passage.
"Ah! Ah!" Brian moaned as he felt the tip of the dildo open up his sphincter and the strange feeling of the dildo beginning to slide into his anal passage.
"Yes that's it, just relax big boy, just relax and let me do the work," Claire said to encourage Brian to let her fuck him with the strap-on dildo.
The pink dildo slipped inside Brian little by little, inch by inch, however, at the three-inch mark Claire could not get it any further in his arse. It was as if it was stuck just that three inches inside him but not any further.
"OH God! That hurts Claire!" Brain called out to her.
"Ok, maybe the medium-sized dildo is too big for you to begin with. I'll try a smaller one. See if you can take that all the way. Stay where you are!" Claire ordered him.
She drew back the strap-on dildo out of his arse and with the small round gape hole of his anal passage, beginning to close over. Claire managed to insert a smaller, thinner purple dildo vibrator into Brian's arse hole. This smaller dildo seemed to work much better. It went the three inches inside Brian and then it went in another inch and another after that.
Soon there was a full eight inches of dildo right up inside Brian's arse and Claire began to rotate and push and pull the dildo in and out of Brian.
"Can you feel that?" Claire asked him.
"OH, Yes that's good I can feel that moving inside!" Brian exclaimed with relief as Claire fucked him slowly with the dildo up his arse. To encourage him some more she reached down between his legs and fondled his balls and stroked his stiff cock, jerking him into a nice pleasurable feeling.
"Right, let's try the medium-sized dildo again, now that you have learned to relax a bit more," Claire told him.
She removed the small purple dildo and mounted Brain again with the pink strap-on dildo. This time Claire found that it easily entered Brian's anal passage, more than halfway with the first thrust from her hip. Working the strap-on, She was fucking the dildo deeper into Brian.
"Oh, that feels big! Just do it gently please Claire." Brian asked her.
"You're learning big boy," Claire told him as she finally got the dildo the full length right up inside Brian. She then began to ride him properly, moving her hips back and forth so that the dildo attached to the strap-on harness fucked Brian. He moaned and gasped as he felt himself being fucked by his wife. Waves of erotic pleasure went around his body and into his mind. He realized that he was actually enjoying the sex.
"Oh, Claire I love you!" Brian called out to her.
"Well, I love you too Brian. I knew you would come around to us both doing kinky sex together." Said Claire.
She kept riding Brian for a good long while, after all a rubber dildo never gets soft or goes limp, it always remains firm, erect, and relentless... Claire took her time riding Brian. There was no rush and in any case, he was in training for the meeting with Frank and Maggie at the weekend and Claire was sure that they would both be expecting to have as much kinky sex with her and Brian as they wanted. That was what Claire had said and done a 'deal' with Frank. Claire had 'pimped' her husband in return for a kinky sex meeting with Frank and Maggie.
Brian was now enjoying his 'training' too. He discovered that he was more than just a heterosexual, straight male. He was coming to realize that he was a man of lots of different tastes and pleasures. Multi-sexual! He was not bi or straight or one specific type of sex, he was multi-sexual, he enjoyed all the different colours of the rainbow, all the different flavors, and tastes of sex. He also realized that Claire was the same as he was. She too was multi-sexual and enjoyed the same sorts of sex games and passions. They were in fact a perfect example of a multi-sexual marriage.