It may sound strange and unusual to some but there are women who like to dominate their men and one manifestation is to fist him. It usually starts with a woman asking if she can use her vibrator on the mans ass. Not to put it in but just run it around his opening. If she has previously rimmed him she knows that he will probably be up for it.
She starts by just using the vibrator on his perineum and gradually getting closer to his anus. As his excitement level increases she might add a wee bit of lube just to facilitate the sliding of the vibrator on his skin. The more he enjoys these new and strange sensations from the vibrator the more he might be willing to take it up a level and allow her to just put it in a little bit to see how it feels. She slides the end of it ever so gently into his hole, just in and no more till he gets used to his anus getting invaded and stretched in a new and unfamiliar way.
His cock is now so hard it feels like it will burst.
As he gets used to the vibrator in his hole he asks her to put it in a bit more and she to starts to fuck him gently with it. As she does this he suddenly starts to cum and shoots ropes of cum into the air as he shudders to a huge orgasm.
That is how it often starts. They both find that they have really enjoyed this new avenue of play and embark on a voyage of discovery to see where it will lead.
This was how it was with me and before long she was using ever bigger toys on my hole and penetrating me with her fingers.
As my hole began to get used to accepting larger circumferences she tried to get her hand in. We had found pictures on the internet of guys getting fisted by women and we wanted to see if I could accept her hand up inside me.
We used plenty of lube and she started with 2 fingers to get me warmed up. She soon added a third and a fourth until she was fucking my hole with them and they were sliding in easily as I grew used to the size of them. She added her thumb into the mix and started to press her hand against my hole. Her knuckles were now stopping her going any further and she added more lube and tried to make her hand as narrow as possible shaping it like an arrow to see if she could get past her knuckles. I could feel her pushing ever harder and told her to rotate her hand as this should help her get further. It was beginning to feel a bit uncomfortable now as I might not be able to take her hand all the way but all of a sudden a short sharp pain and she was in. Her hand was all the way inside me up to her wrist. It felt amazing, the pain was forgotten as she started to fuck my hole with her fist and I started to wank and soon we were synchronising our movements. She was fisting me at the same rate as I was wanking my cock which felt like it was going burst the pressure in it was so great. I started to cum and she increased her fisting rate and I exploded into the most intense orgasm that I had ever experienced. She had been playing with herself as she fisted me and my orgasm had triggered hers as we both came almost together.
I was totally knackered after that and we cuddled up and fell asleep.