How to set LightDM and XFCE to only start when I want them and not at boot - eviltoast

I’d like to keep XCFE for VERY occasional use, so when I’m not using it I’d like to quit it. Also I don’t want it to start at boot. I’ve found a bunch of ways of uninstalling it but that’s not what I’m after, I just want to make sure it is not running unless I start it.