What is a brown leather hole?

My brother is always saying he loves the Brown leather hole when he is lovie dovie with his wife while she eats a cupcake but I dont know if its something i should he repeating I thought it was the cupcakes with the white cream inside (Little debbie snacks) Anyways when I said I wanted a brown leather hole They laughed at me when I said that So Does anyone know what a Brown Leather Hole really is?