r/Fisting

We’d be starting at ground zero, sort of. I use big toys on occasion (though not recently so I should start there) so I think we could get there relatively quickly if it’s something he’s into and committed to practicing but idk how I’m going to get him there.

He’s usually pretty vanilla in terms of sex - which is something to note, I don’t get to do a lot of what I want with him so I shouldn’t feel bad for asking him for one thing right?
But….
He hates getting stuff on his hands
Has previously treated foreplay a just a means to get me wet enough for him to put is dick in me
Has shown no interest in playing with my pussy unless he’s benefiting from it.
Has previously glimpsed one of my (smaller) toys and said something along the lines of “as long as you stay tight for when I see you”
But has said he’ll try to be more open to stuff I want to do.
This is something I want to do so….

How do I even approach this?

So as the title says, I fisted my wife for the first time a few days ago. Its always been a dream of mine. I was just curious about some stuff. So once im able to get in, there isn't enough room to clinch into a fist. Is this something that will change the more we do it? Does the body start to accommodate? Is it just practice? And stretching?