So I made a civilian version of the scepter donkey dick with off the shelf parts from Home Depot for less than $10.00. It's long enough to put into the filler before tilting up the can, long enough to totally invert the can and hold it up high. And flows pretty fast due to the vent on the can:
You can see a bulge in the hose, it fit on the 1" barb tight enough I had to heat it to soften it up. but I did put a hose clamp on just to be safe.
2 1/2" thread to 2 1/2" glue adapter, 2 1/2" glue to 3/4 pipe thread adapter, 3/2" pipe thread to 1" hose barb, 3/4"id, 1 1/4" od hose 24" long.