The thread was just wound, not flattened, meaning that it would add a lot of bulge under the tinsel. A smooth foundation is the basis for a good tinsel body, and a smooth foundation can be accomplished through thread control. If you want to make a really nice looking tinsel or floss body , it's highly important that the thread underneath is as smooth as possible. This is not very hard to obtain. The first thing is to choose a good thread .
Some threads are easier than others when it comes to flattening.
The best of all are undoubtly the Bennichi and Dynacord threads which are extremely thin and made from absolutely parallel strands. These can be made to lie in an almost invisible single strand layer. Of the ordonary threads I have tried, the Monochord is the best for counterspinning and flattening. It's fairly thick, but nice to tie with. The Uni Threads are the roundest of the bunch.