Q: What does it mean for a guy to “go down” on a girl and vice versa?
Dr. Klein: This refers to oral sex: one person putting their mouth on the penis or vulva of the other. It can last a moment or two, or quite a while. Sometimes it leads to orgasm, other times it doesn’t. Other names for oral sex include “giving head” and fellatio (with the penis) and cunnilingus (with the vulva).