keys code
What does keys code mean?
Before the hanky code took over, men flagged with their keys. A bunch of keys clipped to the left belt loop or hip said top/active; on the right said bottom/receptive. Same left-right logic the hanky code later inherited. Quiet, deniable, readable across a crowded bar — exactly what you needed in an era when being obvious was risky.
Origin
An early gay cruising signal predating/overlapping the hanky code; key placement on left or right hip indicated top or bottom status, using the same left/right convention the handkerchief code adopted.