The expression (getting or going to) third base is slang for sexual contact with genitals, especially when it happens for the first time between two people. The expression (being) born on third base refers to having advantages in life by virtue of being born into wealth and other privileges.

What is third base on a girl?

Third base = petting or orally stimulating below the waist, including touching, feeling, and fondling the vagina, clitoris, penis, or testicles.

What is first base sexually?

For example, the top-rated Urban Dictionary definition of “first base” is, “The first step in a sexual relationship, involving making out or French kissing,” but the top-rated definition for “sexual bases” adds, “any above-the-belt touching is included in this base.”