look up any word, like fleek:
 
1.
A bag of weed that you either got for free, already made back your money on, or got for free. You are happy because the entire thing can be smoked free of charge for yourself
I bought a quarter pound, sold some, when all was said and done I made back my money and had an ounce for a happy bag.
by pothead January 06, 2004
 
2.
As it's name suggests, a Happy Bag is essentially a bag of happy. Think of the "happy" in the bag like the massive ammounts of Seratonin(the hormone that makes you happy) that is stored in your brain, and forced to be released when ecstacy is used. A popped happy bag is much like using ecstacy in this sense, as all the happy is forced to exit the bag. However a ruptured happy bag is much more deadly than ecstacy.

A happy bag of normal size, when popped, unleashes enough energy to power the country of Finland for 32 minutes. These extremely powerful blasts and shockwaves of happy explode in a radius of 60 miles. This happy is very infectious.
I heard that Waldo is really a happy bag, and he's hiding because everyone wants to pop him.
by Horoscopejunkie April 19, 2008
 
3.
a bag filled with many drugs such as cocaine, heroin, LSD, and marijuana. it is made into two forms: powder or liquid.

some other names for Happy Bag:
Blue Tit
Moose Knuckle
I got completely WASTED last night by having some Happy Bag.
by dannnnohhhh April 01, 2008
 
4.
The sac bettween a males legs in which his testi's are located, when a woman touches this sac the man feels happy, hence the name happy bag
I have a very large happy bag
by hole September 22, 2003