aqua lung, n. — Green’s Dictionary of Slang

aqua lung n.

[SE ‘a portable diving apparatus consisting of containers of compressed air...which feed air automatically through a valve and mouthpiece to the diver as he requires it’ (OED)]

(US drugs) a long pipe, which is placed in a bucket of water to cool the smoke.

2001

Da Smokehouse Marijuana Gloss. 🌐 aqua lung [ca]- gravity bong in a bucket.