Summary
Companions do their own thing.
Languages
Any
When companions are in a familiar and safe environment, they automatically go into sandbox mode. Instead of following you, they wander around, eat, sleep, sit on a couch.

To allow sandboxing, a cell must:
– be without hostiles and corpses,
– have furniture or an idle marker,
– be visited more than once.

Supports vanilla and TTW companions any properly made companions and JIP CC&C.

Requires JIP LN NVSE and JohnnyGuitar NVSE.

A Skyrim mod doing the same for vanilla followers can be found here.