Stan is a guy's name, generally the nickname of Stanley. I'm not sure what stanning means, but according to google, stan/stanning means to be an obsessive fan over someone. Never heard it before though.
Stuff is a super versatile word. As a noun, it is commonly used and can mean basically any noun, and it is a filler word. Examples:
Get your stuff out of my room
Clean your stuff
We put the relevant files in a folder entitled "Project Victory stuff"
Did you get all your stuff done this morning?
We packed all our clothes and stuff the night before our vacation
Stuff is also a verb meaning to fill with something, and it can be an expression of being full.
Mom stuffed the turkey to make it taste better
The teddy bear was stuffed with cheap material so it wasn't very comfortable
I ate a lot. I'm stuffed.
