A quag is any type of waterpipe or bong that has been (either by design or the user) modified to make proper use of a meth pipe so as to filter the smoke through the water. Typical quags are exactly as stated above, usually using a glass bowl that is basically a normal methpipe with a 90º elbow about 3/4 of the way towards the bowl. Quags are often used in more "meth friendly" circles or where it is unlikely to be found by an unwanted person due to its unmistakable bowl that basically screams "TWEEKER". Not very portable, or inconspicuous, it will get you really high.
Want to load the quag?
Pass the quag!
I need a new bowl for my quag...