すいすい
JD1
(of the way in which something progresses) unhindered / (of the way in which something progresses) quite easily / (of the way in which something progresses) smoothly / (of the way in which something progresses) without a hitch / (of the way in which something progresses) lightly / (of the way in which something progresses) freely / (of the way in which something progresses) without any difficulty