Grandpa's gnarled fingers gently tease his wrinkled asshole, preparing it for the oncoming fisting. He lubes up, massaging the slippery liquid into his puckered entrance. His breath hitches as he Inserts one finger, feeling the tightness enveloping him. He adds another, stretching further, then a third, his asshole gaping and eager. With a moan, he pushes in his entire fist, feeling his insides stretch and accommodate his invasion.