The cat is not allowed in the house.
OK, the cat is allowed in the house, but only in certain rooms.
OK, the cat is allowed in all rooms, but must stay off the furniture.
The cat may get on the old furniture only.
Fine, the cat is allowed on all the furniture, but is not allowed to sleep with the humans on the bed.
The cat may sleep on the bed, but not under the covers.
OK, the cat may sleep under the covers by invitation only.
Well, OK, the cat may sleep under the covers every night, and on the pillow.
Humans must ask permission to sleep under the covers with the cat, only the cat may sleep on the pillow.