What's the proper way to hold a butterfly needle? (for injections)

I’m having to give my ferret subcutaneous fluids. I have a fine supply of butterfly needles from the vet. Only one thing I don’t know–how am I supposed to hold the butterfly needle when I insert it? (Just the needle itself, that is—I know how to tent the ferret’s skin, that I need to insert the needle bevel-up, etc.) Do I squeeze the two wings together and hold them BOTH between thumb and forefinger? Or do I just grab one wing between my thumb and forefinger? Kind of a dumb question, but it’s not a comfortable procedure for either my ferret or myself, and I don’t want to make it worse than I have to.

When I use butterfly needles I don’t do either of those things, I put the two “wings” between my right forefinger and thumb (thumb on top) so that the needle is pointing forward, as if the “wings” are a piece of paper that I want to lift off a desk.

The following link contains a picture of a needle and a real bunny, it’s not horrible, but you have been warned.
I use butterflies like this.

They are designed to be held like the illustration here: http://www.fotosearch.com/LIF145/ped02017/ and that is what I prefer.

It is not a critical matter. However putting a digit underneath instead of pinching the wings may cause too high of an entry angle. In the rabbit ear illustration, the rabbit’s ear is being bent to provide room for the finger on the underside of the wings. This works for an ear but not for other places.

Keep the bevel up. If the skin is tensed and you enter quickly, the discomfort will be minimal.

Exactly.

You know, that makes perfect sense–I just looked at the needle, and when you pinch the two wings together like this (grasping the wings by their textured, “grippy,” faces), the bevel is automatically in the up position.