Our first experience treating Zyelena went poorly. She was my wife's baby, so my wife was going to be the one to stick her. Also, whenever I was the one who did something uncomfortable to Zyelena she'd avoid me for days, whereas if my wife did the same or worse, Zyelena would shrug it off.
My wife got very uncomfortable about the needle, and her nervousness spread to Zyelena. Pretty soon my wife was a frazzle, the cat was hysterical, the needle was blunt and not in the cat though she'd been poked repeatedly, there was a puddle of water that had run down the cat's side when the needle had been poked in and back out through the skin again.
Well, I sent the two of them off to gather themselves while I put on a fresh needle and, after feeling the water bag and finding it cold, warmed the water bag in a sink of warm water. When we tried again, I did the poking while my wife pet Zyelena and spoke to her. It went much better that way. The cat came out funny-looking with a big bulge of water, but calm.
After that my wife was able to use the needle herself a few times when I wasn't around, but it never went as smoothly as when I did it, even when I was alone, so I ended up being the designated needle-poker.
We set up shop in the laundry room where we could keep the other curious cats away, handle water, and have room for both of us. We'd put a towel on the washing machine, warm the water bag in the sink, and hang it from a line I ran through an eye hook I put in the ceiling for the purpose. (At first we hung the bag from a hanger rod nearby, but it was awkwardly placed so I put in the eye.)
At about the second week of treatments Zyelena was quite calm about it. She never responded as strongly as we expected outside the first failed attempt, though she'd try to get away if she thought there was an opening in the first week or so. She never went off and hid after the job was done, though.
It was unpleasant to have to do it, but the results were certainly worthwhile. She had two, possibly three cancers that were working at her all this while. They eventually got her, but she would have gone a lot sooner without regular subcutaneous hydration.