Using an old box, a good flashlight and some plastic from an old presentation folder, I drew the wings out with sharpie.
Then cut a hole for the flashlight and improvised to adjust the height.
Tape your image to a hole cut out of the front of the box and insert the flashlight.
You'll need to level and adjust your image with moving the flashlight closer or further away for size.
It's hard to see in this photo, but here is the traced image in pencil on the wall.
I used a fat molotow marker filled with Midnight's Blackness UnicornSpit to outline the wings.
Then I hand painted in the rest with Unicorn SPiT.
I added shading to the wings with Weathered Daydream and White Ning.
Once it was dry I touched up the areas I needed to and using a wet rag simply wiped off any drips from the wall. UnicornSpit is water based and as long as I don't seal this wall it can be washed off when she gets tired of it. You can seal yours with a light spray of clear sealer in the sheen that matches your wall finish.