My wife is Japanese, and she said that in Japan lots of old people choke on mochi (a sticky sweet made from rice). From what she says, when this happens - the best thing to use is a vacuum cleaner. I also remember a scene from Tampopo[0] where this takes place. Sounds pretty scary and odd, but probably not an entire myth[1,2]

I wonder how effective this is, and what are the risks to the lungs after whatever's stuck gets dislodged.

I guess when you're choking, you'd take that risk if all else fails (if you or someone around you can act fast enough to pull a vacuum cleaner...)

[0] http://www.imdb.com/title/tt0092048/

[1] http://www.accessj.com/2012/01/choking-on-mochi-grab-vacuum....

[2] http://www.japantimes.co.jp/news/2001/01/07/national/daughte...