Bookmarking a particular post (comment)

I can't find any option to bookmark a particular post (comment).

Some threads have some very informative,entertaining and heart-warming posts which dimers want to go over again to learn,to use as a reference or to cherish.It's a nuisance digging a whole thread while looking for a specific post.Can we have an option (button) to bookmark/pin a specific post (comment) ? Thank you!