A ski lift of the 'Poma' (manufacturer) or 'Platter' type, consisting of a single pole/basket seat that you stick between your legs and pulls you up the track to the top of the ski hill. It 'grinds' your winkie (genitalia) if you are not careful or your ski pants are not thick enough. Not really true as I used to ride it at Paskapoo when I was a kid, and my winky survived. As proof, I have a daughter, Sarah, who came up with this definition when she was 7.
Dad, I'm so glad the winkie grinder is not running today.