When (one) was a twinkle in (one's) father's eye phrase
This phrase refers to the time before one was born into this world.
I never knew my father's parents as they passed away when I was a twinkle in my father's eye.
His brother died in a car accident when he was a twinkle in his father's eye.
She believes every day of her life had already been written on God's calendar when she was a twinkle in her father's eye.
From a song, "When You Were a Smile on Your Mother's Lips (and a Twinkle in Your Daddy's Eye)", written for the 1934 film, Dames; derived from the presumption that prior to the conception of a baby, the father was sexually aroused, and this arousal was reflected in a pleased look in the father's eyes.
A remark you make when you are leaving on the purpose of creating a stronger impact
The letter he left before leaving was his parting shot.