A D-spin, according to Mike Douglas, is a cork 3 into a back-full. Candide had it down best when he won the X Games with it in 2000 (d-spin 9, actually). If you watch footage, you can see there is a slight stall after the first 3 where he tucks his head straight back. The second 3 is a straight invert. The stall is what makes it look so stylie, IMO. After 2000, though, people starting using cork 7 and d-spin interchangably.