Arkain suddenly feels Umi's tail lift up and come down with a soft thump. HE wonders why he did that. Then he smerks. Of course that clever dragon doesn't want to give it away that hes inside his tail. It would spoil the surprise. He stays very quiet. He continues to lightly rub your tail sack. He did it light enough to the wold would not see any movements in the tail sack walls but enough so Umi would still enjoy the rubs.