IMO, its hard to say from that picture Tiff. It looks like you're squeezing the bejeezus out of it, but maybe pinching too much. Make sure you start far enough back on the tail and that you're pulling back with your right thumb.

No penes in that picture but not sure anything can be said 100% from that pic. If you're ever in the north valley stop by with it and we can figure it out for sure.