The slang term "keister" is often used to refer to one's buttocks or the rear end of the body. However, it can also refer to a bag or container that is hidden on a person's body, often for the purposes of smuggling or carrying contraband.

For example, someone might say, "I've got the goods in my keister," meaning that they are carrying something hidden on or inside their body. This usage of the term is often associated with criminal activity or the drug trade.

It's worth noting that slang terms related to the body or illegal activities can be highly context-dependent and may not be widely understood or accepted in all communities. As always, it's important to be respectful and considerate of others in any discussion of sensitive topics.