I encountered this once. It was in another spouse swap. I guess I’ve done enough of these to have encountered many variations of you fuck the other guys wife vaginally.
In this one, we will call the other couple Bill and Jane, we went over the ground rules, as usual, before starting. My spouse stated her standard limits of into most anything but you can’t cum in her mouth and you can’t ass fuck her.
At this point Jane says that she is into everything but doesn’t allow anyone but her husband to fuck her vaginally. But she went onto stress that she loved anal. So this restriction was fine with me. Anal is not something that happens often in a spouse swap.
We had the usual beginning. Though while Bill ate out my spouse, Jane asked me to pay some attention to her anus in addition to licking her pussy. I readily agreed. We moved onto my wife sucking Bill’s cock and Jane doing a fine job of getting my cock hard and stiff. Maybe more so than usual as I was excited about shoving my cock in her ass.
My spouse mounted Bill cowgirl and got off quicker than usual. Bill then positioned her in missionary and was happily plowing away. Jane had set herself up bent over the edge of the bed… She guided me as I lubed her up. She requested that I gently massage her ass cheeks as this really felt hot. I then started probing her ass with my fingers. She was moaning in joy. I kept probing and massaging until she said she felt ready.
Usually I would slowly insert myself into her ass. But Jane asked that I just hold my cock and she backed herself into it. She did it slowly. It took some time before the full length of my cock was buried in her ass. I started laughing because I realized that my spouse and Bill were watching intently. Bill had blown his load into my spouse and they became the audience for my performance with Jane.
Now fully inserted deep in her ass I started slowly plowing her. In addition she was rubbing her clit on the pillow that she was laying across. Several times she orgasimed. As I was plowing away her whole body convulsed several times. She obviously found the best way for her to get off was a cock in her ass while rubbing her clit. I eventually exploded streams of cum into her ass.
My spouse and Bill applauded.
Just watching this spectacle had Bill hard again and he and my spouse started a second round. Jane and I showered together. Anal can be messy. From the shower we could see Bill cumming again with my spouse in standard doggy style position. This stiffened me up again. Jane who had said she was up for anything but vag penetration, started sucking me off in the shower. I asked is it OK to finish in your mouth. She said fine. Just tell me when you are almost ready to cum so I can be ready. My legs quivered as I shot another load into her mouth. She swallowed it all. After the load I had left in her ass, my second was mostly liquid without the large sticky globs. But she had no problem drinking it all down rather than letting it slip out of her mouth and down her chin.
It was a different experience and fun for all.
Interesting comment. Many decades ago I first vaginally fucked my spouse. When I was done she had to ask me if i had fucked her. She was so new to all sex stuff she wasn’t sure what had happened