Merp is a word that can be used as a verb or adjective. It goes in place where a word has yet to be invented for an action that causes you to wink or make a sound before doing something.
An example: I saw the squirrel get hit by a truck and I was like, "merp".
Another example: Everytime something goes wrong and everyone points at me I'm like merp.
As a Hispanic we tend to make sounds that can be described or understood as words, merp is just another way to define such sounds.
When you see a hottie and you jokingly say she is merp-alicious.