ok. . . so you and your lady for the evening have been raving it up doing drugs, drinking and anything else that makes your sweat stink in a sweaty night club for about 8 hours.
you finally make it to bed (or wherever it is that takes your fancy) and start getting busy.
only to find your partners genital area stinks of dead fish in cheese sauce. an you'd sooner gag than get lickin and suckin.
we've all been there.

the whale tail is the shape formed when a g-string rides up high over a womans trousers