(Ultimately unhelpful though because I use mosh everywhere these days and that doesn't appear to have anything fancy like this.)
Technically, you don't have to press enter if you've not typed anything (try it in a new SSH session - as soon as you are logged in, type ~? to get the SSH help output), but since the comment was about doing this during an active session without ending it, I figured noting that pressing enter first to be sure you're on a new line wouldn't hurt