Urban Legend has it in 1989 a Siamese cat named Oba would make a Merf sound when happy, sad, being lazy, or just walking around. A group of kids mimicked that cat saying Merf and boy has it spread, some have now shortened it further to Meh.
Add the desired amount to your water pipe to Enhance the flavor as well as the pull of your piece. The more you add, the stronger the flavor and stronger the pull. Rip Responsibly.