(Chiefly British) Perhaps alluding to soccer/football, this is the ribald motto, usually, of men who have been much drinking alcohol together... The resultant inebriation makes them extremely indiscriminate of the target for their ever-increasing horniness.
Rugby player #1: "Nigel, with one more Guinness down your neck, you're liable to go home with a tranvestite!"
Rugby Player #2: "Ay, mate, every hole's a goal, as they say. Cheers!"