A delicious whiskey but it has some burn when it goes down and has a way of sneaking up on you. Similarly to the way your granddad might if he was Jerry Sandusky. Hence the name for this whiskey.
Granddad came over to spend the night and we drank Old Grand Dad together. I trusted him, and the whisky was good, but each shot burned like hell on the back-end. Then I woke up to find that he was rubbing my bum.