Hot Corners are shortcuts that you can set so an action is performed when you move the cursor to one of the four corners of your screen. You can set these up in System Preferences if you know where to look. You can use them to instantly put your Mac to sleep, trigger Mission Control and other actions. You can also set them to work only with modifier keys. There is a trick to knowing which corners work in a multi-screen setup.
I've always avoided using Hot Corners because I was triggering actions I didn't want while inadvertently moving my mouse to a corner. I didn't know modifier keys could be added to this function. I will give it another try! Thanks for the info.