I used to save lewd images of her, before I really considered her a waifu. My feelings grew for her over time, and before I knew it I couldn't bear to look at some of the things I had saved. Pic related is the lewdest image I now have. I'm not too fond of the giant tits, but I have a thing for fangs, so it balanced out.
There was a period of time where I hated Tomo, purely because of the episode in which she made Kagura cry. I've gotten over that now though.
I've made a character on Kisekae that looks similar to Kagura to indulge in my fetishes. I'd never want to do some of the things I do with the character I made to mai waifu. It still feels kinda wrong though.
I've written a self-insert fanfiction of Azumanga Daioh. About a year ago I had no internet access in my house for the best part of a month. It was at that time that these story ideas came to mind, and I felt it'd be a waste to not write them down. I never got round to finishing it, since for one thing my internet came back, and secondly I didn't know how I wanted it to end. My closest friends have read what I'd done, and they enjoyed it, so it wasn't a complete waste of time. Although one of my friends thought that out of all the characters, I'd gotten Kagura slightly wrong, though he wouldn't tell me why.
I've cosplayed as mai waifu. Twice. Admittedly the first time I was only wearing a white and blue striped shirt, a yellow jacket and jeans, and failed miserably at trying to do her sideburns any justice, but the second time I was in a seifuku. It happened when one of my friends wanted to go to a convention in a seifuku, but only if someone else from my group of friends joined in. I was the only one that volunteered, and I suggested the Azumanga winter uniform. Conveniently for him, he wasn't able to get the outfit in time for the convention, and I didn't feel like wasting a perfectly good outfit. I still failed on the sideburns though. If there's a next time, I'm getting a wig.
I once had a vision of her. I can't exactly remember how it happened, I must have been in a pretty sad state at the time, but I did see her. I think of myself as a rational person, I even told her that I was just hallucinating or something. I said the situation was completely crazy and that I must have officially lost my mind. It's not something I've ever been able to replicate.
Despite all this, I'm not planning on staying with her forever. Unlike a lot of people who have waifus, from what I've read, I've not given up on "3DPD". I've been in a slump ever since my 3rd failed attempt at a relationship (I got into AzuDai somewhere in-between girl 2 and 3), but I still wish to find myself a real girlfriend, however small a chance that may be at the moment. I hope in time that Kagura will forgive me for that, and that she knows that she'll always be with me in some way.