I need to make a rooster tail for a 2nd grade boy. Everything I have tried is too heavy and falls/flips?

I have a string of real rooster feathers approx 6-8 in in length sewn together for a strand about 10 in long. I have tried to attach to a piece of foam with a coat hanger woven through. I then attached to a belt.

Attach the feathers to either a piece of starchy, stiff cloth (to be pinned to pants) or to a piece of cardboard which can be glued, taped, tucked, or I guess even pinned to pants or a belt.

Maybe use styrofoam (from the craft store, or left over packing material) rather than the heavier upholstery foam. Not terribly durable, but maybe it doesn't need to last long?