Standing next to the air grate in Tanglevine.
The Air Grate is a location in Tanglevine Jungle and launches the player into the air once it is stepped on. It is also similar to the cannon in Presto's Grove but instead of launching once, the player goes up and down three times before landing. On the third and final bounce from the grate, you will land in a random location in Tanglevine Jungle.
There are green Onakasi Gems in bubbles floating in the air that can be collected by passing your mouse cursor over them while flying up from the grate. It is difficult, but not impossible, to grab them all in one trip through the grate (three bounces) and receive 30 coins.
This is also the location where you can find the Grappling Hook and Rope in a tree, which is needed to get into the Tree House in Wildwood Glen.