Do male horses only put the thing out while mating?

Male horses, or stallions, have a penis that is normally retracted inside the body. It only comes out when the stallion is aroused and ready to mate. This is different from male humans, who have a penis that is always visible.

When a stallion is aroused, the penis will become erect and protrude from the sheath, which is a protective covering that surrounds the penis when it is not erect. The erect penis is firm and has a bulbous tip called the glans penis, which is where the semen is released during ejaculation.

Once the stallion has mounted the mare and achieved sufficient stimulation, the penis will be inserted into the mare's vagina and ejaculation will occur. After ejaculation, the penis will retract back into the sheath.

It's worth noting that stallions typically only extend their penis during mating or certain reproductive procedures. Outside of these specific contexts, the penis remains retracted and concealed within the sheath.