noun: A merkis is a postiche that protects the upper anal region more specifically your 'crack,' sphincter, and buttocks from the harsh elements of day to day life. Generally only worn by village people impersonators and baby eskimos to keep their baby hineys warm.
derived from the English word, merkin, meaning pubic postiche.
That Frat Bunn is such a big gay merkis!
Look at that baby eskimos hiney! It's got a merkis!
God dammit PJ! It smells like hot merkis duck butter in here!