A quag is any type of waterpipe
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 meth pipe
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.