slink in
To enter some place in a quiet, sneaky, inconspicuous, or furtive manner. The burglar slunk in without making a sound. Marty came slinking in the room, late to class as usual.
slink in(to something)
to creep into something. The cat slunk into the hallway and lay down in the middle of the floor. I left the door ajar and a cat slunk in.