Use the following code to embed the video in description. Just change the video url. This should work just fine.

<div style="position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%;"><iframe src="https://www.youtube.com/embed/NGe9ZGLlWXA" frameborder="0" allowfullscreen="" style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe></div>