As I recall from another thread, I believe the adjective you're looking for is "stonking" - or the adverb "stonkingly" ...
As in: "stonkingly great breasts". 
-D'Artagnian
I believe it comes from artillery spotting... I remember reading a story where a junior Lieutenant was calling for, not three salvos of 155mm howitzer fire, but three "stonks", and having to be corrected by their sergeant when they got it wrong the first time (salvos).