I used to have them every now and then when I was 8-13 or so. They usually appeared when I hadn't eaten in a long time and then started eating. Which was annoying as it'd always come flowing after I took the first bite of something and then having to go make it stop bleeding , making the food all cold by the time I got back. Last one I had was three years ago, and before that ages ago.

To stop them I lie down.