Note: This question is how to send an Insert keypress to Microsoft Windows running directly on Apple hardware (not through a VM). This is not about how to use Insert in OS X or through OS X to Windows running in a VM. See here or here for non-Windows Q&A's.
Somehow in my code editor and command line I keep toggling the Insert key, but I'm not sure how. I can toggle it by clicking on OVR/INS in the status bar, but what is the key combo that I'm magically fat fingering?