I rolled two antlers of similar size and the right length and sculpted them to the back of the head. I used a piece of semi dry clay to help keep the wet clay from sagging. I used the score & glue method to stick the two antlers together, it would also be plausible to make one flat antler and carve it into two separate staves. I then cut a hole in the rear and worked the ends of the antlers around it to disguise the edge.