All good ideas! I've found that especially circling...can be extremely effective on a sensitive sub. <grin> That, and even a light almost pinching stroke, but not quite pinching...like you're going to pinch them but instead your fingers are positioned like you're about to pinch them...then they just lightly brush them as you pull your fingers upwards, if that makes sense? A similar motion works very well on a sub's cockhead too.