Directly below the thumbnail picture? The description right to the picture often is too short to be useful, it would benefit from a line more too that easily would fit then.
Currently it looks like ...
ChannelOwner • 11 hours ago • Mark watched
... and a small "icon" (I use [X] here) added to the start of the line ...
[X] • ChannelOwner • 11 hours ago • Mark watched
... as additional link to "Mark watched" would be a minimally invasive change and keep the readers' pointer position in the same "column" independently of the length of the other fields. Sure moving the whole "Mark watched" link to the start of the line would solve that too, but maybe users would prefer the smaller change? Or would it be confusing to have two positions for the same request?
Mark watched • ChannelOwner • 11 hours ago
Maybe that one is just more consequent?