Well... If you're dehydrated, then it will be harder, but what you want is your inside temp hotter that the ice cream.
Try drinking a cup of hot water, like the temperature for tea (but don't hurt yourself!!) This will put hot moisture in your mouth. Take a big bite of ice cream onto your spoon, take a breath (not a big breath or anything, because that might dry out our mouth.
Place the ice cream on your tongue, while making your tongue a 'bowl' shape, close your lips, keeping your mouth open. See if you can keep the roof of your mouth from touching the ice cream, then wait about 3-5 seconds. Open your mouth, and make a slow "huh" sound. Think "hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh."
It's best if you let the air drift out of your mouth. I used to do this thing when I was a kid all the time and pretend it was dragon's breath. ;-)