That is actually a good idea, preferably an oil less rotary vane blower.throw a air pump in it !
Bubbles are not only for the tub
The Boxers we had growing up slept on their backs but our only German Shepherd that did was a male with prostate cancer in the last weeks of his life.Marvin sleeps on his back.
Our male GS Cisco liked to lay in the grass on his back and writhe. I used his picture as my screen picture after retirement to remind me to wind down, smell the roses, and enjoy the sunshine!