I often do something like this:
Copy some stuff
Go to where I need to paste it
Paste it (C-y)
Kill the rest of the line (C-k)
Select what I just pasted, and copy it again
Repeat steps 2-5
The whole "...
Emacs has a secondary selection (not the X11 selection, rather the mouse-secondary-overlay).
On my system holding Alt-LMB dragging sets it.
How would I check if there this selection is set in elisp?