Trying to add weapon bob/sway like doom classic

Not looking for a fancy solution just would like to know anything that works I have a flipbook thats a child of my fps camera and I’m simply trying to get the flipbook to sway back and forth independent of the camera like you can see in classic Doom I’ve tried a couple of different ways but there’s not much documentation online about something like this any solution would be greatly appreciated again not looking for something too complicated just something that’ll work

edit: even just a simple up and down bob would be perfect! lol