dad dick
That one time you saw your dad's pecker when you were like six, and it was so big it scared you for life.
I saw my dad's dick when I was six, and now I still have nightmares.
My little brother walked in on my dad and screamed like he was being chased by a bear.
That time I saw my dad's dad dick, I ran out of the house and didn't come back for a week.