A spinning hook kick also sometimes works good if you are sparring open stances (facing same way) and you opponent is crowding you. The last thing he's thinking is a kick, so jab a body shot and then spin hook to the back of the head. Open stance makes the opponent's counter attack somewhat harder.

A spin hook is pretty risky in terms of spinning into a counterpunch, precarious balance, your nuts being pretty exposed, etc. and it's hard to hit the target so it is not my "go to" technique. However, I still try one every so often because there is something VERY disrespectful and satisfying about putting your heel across somebody's chin like that...