Maia Artful

Hi, I want to up my game a bit with tattoo creations. I saw a video once upon a time on how to use photoshop and "stickers" to add tattoos to a 3d model, instead of having to try to match things up with a flat UV map. Does anyone know of anything like that or can give me any pointers? I'm just getting started here, I doubt I'll be much competition. thanks!