Pairing, also called pairing, can refer to people or things, or two people together: for example, one or several pairs of men and women together, chopsticks, shoes, socks and so on. Are in pairs, so are animals.
Being single, also known as playing single, refers to being alone with one person or one thing: for example, single men and women, being alone with one person and one animal, drinking alone, a sock, a lonely goose and so on.