My pet seems to be switching to aggresive randomly and pulling stuff. i always have it on passive or else it breaks cc. but somehow it likes to switch and wipe our group.
if youre using bartender theres a function called "key bindings" when you use the /bt command, it lets you set keybindings for all visible and clickable abilities/macros/scripts/whatever-you-can-click, simply by mousing over and press the desired key you want to bind it to.
Or you can "go fish" in the standard blizzard key binding interface. I have zero clue what they chose to call that function though.