The first thing that will come to the non-horsey mind is the day they lined up for inspection, the sergeant asked for a volunteer, and everyone else took a step back.
Note to the non-horsey: don’t panic if your friend says, hey, I have an idea, let’s stick out my mare. There is no tricking, or picking up and carrying involved. (Normally)
Sticking Out is slang for measuring how tall a horse is. Horses are measured with a measuring stick that has line markings at meaningless intervals. You won’t find out how many feet tall the horse is without a calculator. Horses are measured by how many Hands High they are. And yes, they are measured by hand (manually) so congratulations, you got that part right!
Unlike people, horses are not measured from the ground to the top of their heads. Horses are measured from the ground to the highest point of the shoulders (withers, in horse speak). If someone says: “my horse is 16.2″ this translates to “my horse is 16 hands + 2″ tall.”