OK so don't let the sensation fool you. It feels like nothing is happening when you put it on. Then when I touched my eyebrows again after a few minutes I was like "Oh! They're gelled in place!".
If you're used to pomade or thick gel, just trust that it's working, and don't over apply like I did on my first go.
I now use the tip of the wand to apply the serum, then I use the brush regularly to just fluff and shape. Easy.