Seamstress Help Needed...........

I made Tashsa and Carley a tunnel using fleece and regular fabric. It's about 18 inches long and it has a strip of 1/4 inch boning at each end and in the middle to at least keep the tunnel upright. It washes well but my problem now is that even though the boning is keeping the tunnel tubular in shape, the ends don't stay upright.

Any ideas or suggestions? Thanks