Love everyone who's saying, "My House, my rules."
This is a great life lesson. The rest of the world is not Mama. This knowledge really is a fundamental element of success.
Do you x-stitch? Ever made a sampler? How about hanging up a pretty sampler which reads, "My House. My rules." or, "Grandma's House. Grandma's rules."
You could add pointing at the sampler to your routine. You'll have The Look and The Point.
My fave is the "Life's unfair." sampler. When they hit the "That's not faaaaiiiir!" age, they'll be biting their tongues and holding back. No kid enjoys having their whine interrupted by a dismissive "Life's unfair."
Ah, good times. Thanks for the memories.