When a statement is misheard between two or more inebriated individuals resulting in one thinking the other said something completely different.
Initially derived when one drunk individual misheard another and thought he said mud cake tuna. After finding no reference to Mud Cake Tuna on the internet, a definition was derived based on what had happened. Essentially resulting in the Mud Cake Tuna that happened creating the phrase and definition simultaneously.
Person 1: What are those monkey's doing?
Person 2: Did you say "mud cake tuna"?
Much like the tuna tunnel the gooey tuna tunnel refers to the female sex parts. However the gooey tuna tunnel is in fact more gooey suggesting its previous use by another male or even sea mamal wang. The extreme gooeyness explains this