In my opinion, the very best setting to practice is anywhere outdoors, whether hearing birds, frogs,cars, farm animals, people talking, leaf blowers, or lawnmowers sound takes on a different feel when there are no walls.
it’s also a good way to get inspiration for different vocalizations through the Didgeridoo. always try a wide range of sounds,don’t be afraid to straight from animal noises and do something silly.  Michael Winslow from police Academy made a whole career out of making silly sounds with his mouth and that dude was awesome!

(he was also in Spaceballs. May the Schwartz be with you:)