With the vid open in youtube, I pause it, look under and click on share, it pops up a URL that is already highlighted, I right mouse click and copy the URL and then just paste it here. Like others, I have found it works most of the time, and is sometimes necessary to put the URL on a separate line, with a space and a return after it.
https://youtu.be/_7FkcJaFKDs
and sometimes that doesn't work, hmmm, lets edit that without the s following http like someone suggested