I'm guessing that you are getting hung up on the fit between where the cape wraps around the neck and drapes over the shoulders. That's a pretty thick piece with a lot of stress on it from the molding process. You could thin it a bit by grinding out some of the thickness from inside and dress it with sandpaper, then using hot water to finish. The easiest way for me was to use a hot air gun with a fine directional tip on a low setting. I didn't thin the plastic in advance, so it took a while. In either event, go slow and test fit repeatedly - it's easy to bend too far when things are hot, so test fit often.