When someone calls a male stranger "Sir".
Specifically applies when the guy who got 'sirred' hasn't accepted that he's getting old and doesn't think there's enough of an age difference to warrant it. Doesn't count during retail transactions or any circumstance where the younger person is working and trying to sound professional.
Male equivalent of 'Ma'amed'
20yo male to stranger passing by "How are you, Sir?"
30yo male to stranger "Uhhh good man"
30yo male to friend "Holy shit that guy just sirred me, do I really look that old!?"
friend "Yes. Yes you do. I always thought you were like 45. Anyway you gotta let it go man, you're getting fucking old!"