Lori,
Here's the trick the vet showed me. I've done this sub-q 100cc thing 30 times in the past 9 weeks...
I scruff the cat with the last three fingers of my left hand, and make the "tent" with my forefinger and thumb. Then, just before you stick the needle in, "shake" the tented skin pretty good and when you stop for an instant, slide the needle in. As long as you are tented high enough, and parallet to his spine/body, all you'll be touching will be the outer skin when the needle goes in. Then I don't let go with my left hand. I turn the drip all the way up with my right hand, and then sort of rest it back on the plastic end of the needle to make sure it's still all the way in. Then while still scruffing him, I talk to him and scratch him under the chin and rub his head to distract him.
I do all of this sitting on the floor with my legs circled around Bob. His head is about level with my left knee and most of the time, he'll just lay there and rest his chin on my leg and purr. A couple of times he has tried to get away, and that scared the hell out of me. Once he pulled the needle loose and I had the same flood you experienced. Luckily I grabbed for the shut off instead of the needle. I was surprised how far and fast the liquid shoots out too. A couple of times, Bob has cried. Once when I stuck the needle in, and once when I guess I didn't have a good spot and I think that pocket filled before the 100 ccs finished dripping. I let him have his way that time and just shut it off after 74 ccs or so. I've also had one incident where he laid down right afterwards while waiting for his cut-up shrimp, and when he got up, there was a good sized pinkish puddle where he'd been laying. That one time, he did bleed just a little. Every other time, it's gone really well though. Usually you'll get some leakage but not a whole lot. I saw you massaged it, or the nurse did, after shooting. I've never tried that only because Bob doesn't seem to mind looking like a camel. Also, it gives me a better idea how quickly or slowly the fluids are being absorbed if I just leave him alone.
Just like ear pricking and insulin shots, this gets easier each time, for you and for Tom. I know you've been at this a whole lot longer than I have, but the sub q fluids, I've got a good bit of practice at. If you have any questions, feel free to PM me.
Carl in SC