Here's a very good video of making a butterfly sculpture in soft glass. The technique is very nice and makes it look easy.
You may be surprised that the artist can leave the wings out of the flame and doesn't keep them warm. One of the keys to working this way is that you plan your work so that you can finish an area and let it cool, and NOT go back in and re-heat it. Once it cools down, you never go back.
Notice that at the head of the butterfly - the artist leaves a skinny bit of glass sticking out? Makes it look like a beak - so the initial stages look more like hummingbird. Then the artist reheats this to add the antennae. This is the other key to working this way. Any place that you need to go back to, you need to leave a projection of thin glass, thin enough to heat without shocking. Think of the difference between heating a stringer and a rod of glass. The stringer is not going to shock when you put it in the flame, because it is thin.
I only wish this video had been shot through a filter so you could see better through the flame. But it is still very worth watching.