You can check out my cake that I did for my girls bday. It's in my photos. I mixed 1/2 MMF and 1/2 gumpaste and used black americolor to color it. I rolled it out, but left it thick, then used a circle cookie cutter to cut them out. My cake has the hat, so I had to use the same cookie cutter to cut half circles in about the bottom 1/4 of the ear, then I put that part against the hat to make sure it was flush with the hat before it dried. Does that make sense?
I put a little water/powdered sugar mix on the part that was going to need to stick (I didn't have piping gel, that may work better), and 2 toothpicks into the bottom of the ear where the cutout was and stuck it down into the hat. Then I put a toothpick in the back part. Like one end gently in the back of the ear, the other end on the hat to kind of "prop" it up until it dried. By the next morning (I finished after 2 a.m.) the ears were good and dry and I took that extra toothpick out of the back, but not until I got it safely to the park and on the table, just in case LOL Good luck!