When you mix this shot, you don't really have to measure out the ingredients. I have always just filled a shot glass about 2/3's of the way with the peach schnapps.
You then layer on the Irish Creme to fill just under the amount the shot glass holds. It helps to pour the creme onto the back of a spoon and let it flow onto the side of the glass from there. It will make it a lot less curdlely.
Using the spoon method again, layer the blue caracao underneath the irish creme. you just want it as a thin layer.
Now the fun part! Take a few drops of grenadine and drop it through the middle of the drink. It pulls the irish creme through creating a curdling effect.
Just be careful not to stir it around to much, otherwise you can get a cloud or irish creme instead of the cool looking tendrils.
Now it may look like you are about to drink mucus, but it tastes amazing!
A video: http://www.youtube.com/watch?v=OQ1WzuUmaEw