How words are described
Both words in one sentence
- The birth of a boy and a girl instantly creates a fully formed family of father, mother, son, and daughter, putting all of the family relationship tropes into play, without any perceived bias by making the boy or girl older and in an authority position over the other.
- Three-Way Sex: both girl/boy/girl and boy/girl/boy.
- Maybe the logic is to do the LEAST suspicious thing a boy and girl (or, in some cases, a boy and a boy or a girl and a girl, depending on the situation) would be doing in a dark room or alley, or because it's difficult to recognize someone's face when it's mashed against someone else's.
Source: Fake-Out Make-Out
Google Ngram Viewer shows how "boy" and "girl" have occurred on timeline