Place the hoop or spot on the court. Tossing player must stay here when tossing the ball. They are trying to get the ball past the player across the net, who is trying to take the tossed ball as a volley and put it away. Tosser gets one point for each ball they get past the volleyer. Volleyer gets one point for each clean winner. The tossing player must not leave their spot/hoop, but if they can touch the ball before it bounces twice, no points are awarded.
Tried this with some orange ball players recently. I didn't have any hoops handy so I made both players stay in one half of the court, facing each other straight ahead in their respective service boxes. So the tossing player got an advantage of having a larger area to work in, and the volleying player had to hit better volleys to keep it away from the tosser. A great exercise for working on angled volleys!
The main difficulty with this activity is what kind of tosses to allow. Immediately had to outlaw lobs and constantly had to remind them to toss underhand only. Also no fair tossing outside of playing area. In other words toss had to be on same half of court we were playing on, more or less straight ahead. I was hoping they would figure it out on their own, but I had to break down and suggest the importance of figuring out which side was the volleyer's backhand side and perhaps try to pass them on that side?? Light bulbs went on. Tossers gained additional advantage by keeping the ball low - another valuable lesson. This one they learned on their own after a couple of unfortunate high tosses turned into stinging volley winners!
We also modified this game to a team format, first to 11 wins, best two out of three. By the end of about 20 minutes of play we had refined the tossing and also had some great angled volley winners coming off some racquets. We finished the hour playing doubs, trying to put their new-found volley skills into practical application. Highly recommend!