The hand is relaxed and gently cradling the cue with the classic grip. I consciously have elevated my right forearm from the elbow as I am taller, this places my arm in a position from which to comfortably thrust the cue forward. My upper arm and lower arm are near a ninety degree angle. (I explode the 90-degree pool myth elsewhere.)
Your arm may hang down naturally as you are comfortable or try my raised arm move.