Bleeding like a stuck pig
To bleed an extreme amount of blood. The expression likely comes from the method that farmers would slaughter their pigs. Pigs, when injured, release a bodily chemical that ends up making their meat taste bad. Because of that, farmers would stab the pig with a knife, specifically in an area that draws a lot of blood (such as the jugulars).
Did you see that dude get shot? He was bleeding like a stuck pig!