How are you trying to do this? Are u using an adhesive to keep the ribbon in place? I would check the tutorial section over at embroidery library and see how they do it. Also the stabilizer that you are using should be a medium strength. If you are using a tear away that may be the problem so switch to permanent.

I did hair ribbons for a twirling team some time back, and I did not use a stabilizer on the grogain. Try the tutorial at emblibrary, and make sure that you do not stretch the ribbon when hooping.

I have used Sticky adhesive and had no trouble. Hope yours works out. Here is a flower for you.

When I tried this I stitched the ribbon around the outside edges to cut away stabilizer after centering and etc.