Archaic spelling of
bong, also known as a
water pipe, used for smoking various herbs. Today in the US and and around the world, bhongs/bongs are used most frequently to smoke
marijuana. A bhong is somewhat similar in function, and identical in purpose, to a
pipe or
chillum. I suspect that Bhong's spelling comes from a
Hindu word for pipe. The spelling "bhong" seems to be used more frequently in places like France, as opposed to the US, as far as I can tell.
Somewhat redundantly, a US Military web site says: swat: A draw of marijuana smoke from a bhong water pipe.
source: http://www.dss.mil/training/adr/drugs/drugsLZ.htm