Any type of glass jar to keep your weed from stinking up your room. Typically made from any type of food jar such as jelly or pickles. You can use a mason jar but using a food item is just more fun.
Friend: Bro wtf are you doing with that jar of pickles?
You: It's my yum yum jar , can't let my old lady smell my loud
You: Don't throw out the jelly ma!
Mom: What the hell do you need it for?
You: Yum Yum jar you wouldn't understand