Crabs are tiny pubic lice that can be transferred by sexual interaction. They suck the blood of the host and make your private areas itch a lot. Also they can leave grayish-blue marks on your thighs or there can be yellow blobs (nits- they are eggs) on your pubic hair. There are treatments. If you go to your doctor he/she can prescribe medication to get ride of them. It is helpful to wash all your bed sheets, clothing, and towels to make sure they are all gone. It's kind of hard not to get crabs when your partner has them because a condom doesn't cover the whole pubic area. Crabs can be found in not only the pubic area but any places on your body with coarse body hair such as legs, armpits, mustaches, beards, eyebrows, or eyelashes.