1. Doing things "quietly", i.e. calmly and even if the activity wouldn't ordinarily make noise anyway.
2. "Gently, bently." As above.
3. "Don't break the toy". Used especially at Christmas when we were trying to open or start something with too more urgency and insufficient care [even if it wasn't a toy].
And one other, on a different topic:
"You are the man for the job!" - said every time I went for an interview. Great confidence to have in your lad! Then there was Dad's urge at these moments to "exercise your personality".
Pic of the day: Aunt Mollie pretends to look impressed as Mum proudly models the latest in lightshade chic c. 1962.