When I look at photos of tails with GP Tippet on line I am often struck by how excessive they are. For a trout fly 6 fibres will produce an effective tail on a size 10 or 12. That really is all you will need. Usually I don't bother too much about the feathers rolling about so long as they don't roll around the hook shank. If they do roll around the hook shank then the problem is with your pinch and loop technique. (I'll not go further that way as that isn't the problem you stated).

If you want a really first class tippet tail then there is a technique that can be borrowed from classic salmon fly tying. Simply take a section of the stem of the feather, fold it in half, pinch and loop it in. You can get lots of these sections from one tippet feather.
Black Pennel_0001.jpgBlack Pennel_0002.jpgBlack Pennel_0003.jpgBlack Pennel_0004.jpg
Hopefully that will address your concern, though I doubt the trout will be bothered.

Cheers,
A.