Crafty Shield protects all Pokémon on the user's side of the field from status moves. It does not protect against damaging moves or moves that target their user. Crafty Shield can be used consecutively without failing.
Crafty Shield even protects from status moves that can bypass Protect, Detect, and Spiky Shield (such as Sketch and Play Nice). The only status moves that target a Pokémon other than the user it cannot protect from are Perish Song and entry hazard moves. Because it cannot protect against moves that target their user, it will only protect a Pokémon from Acupressure if it targets a Pokémon other than the user.