Something EVERY SINGLE OWNER of a stallion or gelding should know. What is a bean? A bean is a small or large (I've heard of some being the size of golf balls) substance that is normally rounded, sometimes shaped like an oval, that looks like clay. These get in the male parts of the horse, in their sheath. They can be extremely painful & it is very important to get them out. This is why sheath cleaning is important, these are VERY VERY VERY painful. Red just got one taken out.