I’ve heard it explained many ways:
It means ‘scratch my butt’
It means they are keeping tabs, albeit lazy, on where you are.
It means they are protecting you by putting themselves between you and any ‘harm’ that may come your way.
It means they are claiming you as ‘theirs’
It means they are insecure and need to know you are there.
It means they just want to be close to you.
It means they are being dominant.
And sometimes, like Carol said, it simply means they are being a Rottweiler.
