Painting on collision similar to (de blob or meat boy running system)

So I have been looking around the internet and have not been able to find any help. So basically what I am trying to do is make my player paint a color on a wall once it has touched it. Trying to get it to look like this where you touch something and it paints a decal.

My game looks like this;![alt text][2]

Essentially it is a platformer but it has this effect to it. The effect it crucial for the main gameplay element I had in mind. Any help or advice would be greatly appreciated! [2]: /storage/temp/24589-2014-04-01_1406.png