The first area this becomes available is Stage 4 (Old Pier), there are multiple holes in the pier throughout this area but about half way through the pier section is an ideal spot as multiple enemies jump onto the screen from the far side of a large hole and are in prime positions to be thrown down.
Simply grab one of the enemies by walking into them from the front and then hold the direction pad towards the hole and press punch at the same time. Just be careful not to get thrown down yourself!
I recorded a video to demonstrate this method in action and have included this below. If this helped you out, please up vote the solution and throw a like on the video.