Many years ago the band I was in played support to Dr Feelgood. Being fans of theirs me and the guitarist went to say hello to them in their dressing room after the gig. When we went in we didn't notice there was a second door next to the one we came in through. After a brief tongue-tied chat we went to leave, my guitarist opened the wrong door and I followed him, closing the door behind me, into the bathroom.
Coming out of the bathroom back into the dressing room where our heroes were trying hard not to burst out laughing was mortifying.
PS. Lee Brilleaux was a really nice bloke and gave us a beer each