I am using Mac OS and emacs -nw (the terminal mode).
I don\'t know how can I paste things (having been implemented by M-w in emacs -nw) outside the emacs.
If you want a way to place the contents of the emacs region onto the clipboard only sometimes, as opposed to every time you do an emacs yank (which causes the clipboard contents the be overwitten all the time), you should check this answer to a related question:
https://stackoverflow.com/a/19625063/3363328
I found that it solved my problem much better than setting xclip mode.