Start in a neutral stance, like you would for a spinning hook kick.
Touchdown Hook
It's also called meia lua de compasso in capoeira. It's basically a spinning hook kick where you touchdown with one or both hands. You can also think of it as a cartwheel, where one leg never leaves the ground.
Tips
Because you lower your upper body so much, it makes it a bit easier to get a high kick out. You should still have a good amount of flexibility for maximum extension.
You can also touchdown with one hand hand only, to add some variety to the kick.
...or with no hands at all. This requires more flexibility, so you won't lose balance.