The plastic tail is an ‘Ass Saver’. A highly flexible strip of plastic designed to snap into your saddle at a moment’s notice to act as a mudguard and save your precious ass. Play the video to see how simple this is.
I have used temporary mudguards before. I have one that clips to the seat post and holds a much longer strip of plastic much closer to the wheel. I still get a wet butt. So I was dubious. But at an outlay of less than £10 including international postage I took a punt.
The video also shows how easy it is to remove the Ass Saver and store it under the saddle. I’m sure it is if you don’t have saddle bag. Sadly, not having a team car following me around, I do have a saddle bag to carry spare tubes and tools. So my Ass Saver stays on permanently but that is no problem because it weighs as good as nothing and the disruption to my aerodynamic flow makes little difference to my performance compared to my rounded gut.
Full product details at Ass Savers.