Green’s Dictionary of Slang

(US gay) to have the company of or act as a ‘beard’.

1972		B. Rodgers Queens’ Vernacular 30: ‘Are you bearding tonight or is that your lesbian mammy?’.
1985		T. Fennelly Glory Hole Murders 112: ‘You knew him well, then?’ ‘Only as a friend of H.R.’s. He used to beard for us’ [Simes:DLSS].
1991		S. Cutler Best Performance (1993) 284: ‘She says Rollins was supposed beard for him by pretending they both went to get a bite’ [Simes:DLSS].