Pungent, smelly vagina. Usually denoting the presence of something to be later cleared up by antibiotics. The origin can be traced to the streak of grey slime left on the top of your johnson after hiding the salami in a 'trich' infected wench, and it's probable similarity in smell to cut-up dead fish parts used to lure sharks into surrounding waters.

A casual invitation / threat used by an individual that is not afraid of fucking someone up.