I think it's about a guy who's mentally moved on from where he is at the moment (romantically or otherwise) and is still being kept there, even though he's not really a part of that scene anymore, and as a result is kind of excluded, so he turns to the things that he will always love/be into/that love him for comfort, because in the case of the last line 'a boys best friend/is his mother or whatever has become his pet'- your mother is always your mother, and your pet is always your pet.
I think it's about a guy who's mentally moved on from where he is at the moment (romantically or otherwise) and is still being kept there, even though he's not really a part of that scene anymore, and as a result is kind of excluded, so he turns to the things that he will always love/be into/that love him for comfort, because in the case of the last line 'a boys best friend/is his mother or whatever has become his pet'- your mother is always your mother, and your pet is always your pet.