A phrase shortening and combining the words lick and them meaning "lick my balls"
Dave: Want to go to the mall later ?
Steve: Lick em dave.
A phrase used to show scorn; can be used by/directed at either gender.
Also an interesting catchphrase used by the hottest girl in the world, Hannah Ranck, when speaking to me about certain people we dislike.
She called you a bitch? Tell her to lick em.
World War II baby, LICK EM!