What does black handkerchief mean in gay sex?

What is black handkerchief?

Where a person is seeking some heavy sadomasochism sex play, by displaying a black handkerchief.

Definition

Where a person is seeking some heavy sadomasochism sex play, by displaying a black handkerchief. Generally indicative of someone into extreme pain. When worn on the left, indicates they are a top, the dominant one. Worn on the right, indicates they are the submissive, or bottom.