A derpi is the coming together of a Jessi and a gussi usually in an online game form.
A derpi may also be used as an affectionate term of endearment by one of the aforementioned or by any other user. The term derpi stems from the origin, derp.
Onemight refer to another individual as a "derpi" if they have done something silly.
When one has diarrhea and then out of no where a solid piece of shit flies out of the ass and into the bowl, splashing the previously laid diarrhea onto ass and exposed genitals.
Dude #1: What took you so long? The movie is about to start.
Dude #2: Had a Derpducken dude. Had to make sure shit was locked down and everything was clean.