Yeah, just to repeat what everyone else has said, add water to it. Enough so that it's of the same consistency as any "normal" paint. And either way you should water down your paints when you paint. Meaning "normal out of the pot paint" + water. Since you'll probably ask, 4or5 : 1 paint to water. It gives you a much more even base coat, although it takes a few more coats than normal.