When you are urinating in an empty washroom, and another man decides to use the urinal directly next to you instead of choosing literally any other urinal to pee in. After which, scoping your penis with a quick glance.
"Dude I swear to god you could of chosen any other urinal, but instead you check mate me..."
A situation in which failure is the only option available.
There are no other moves left. You just have exhausted every other possible option and the chances of a plan actually working after a check mate situation are zero to none.
Steve: I have to read 60 pages/write a 20 page thesis that's due in an hour and I haven't started. WHAT AM I GOING TO DO?
Friend: I don't know what to tell you- sounds like a check mate situation to me.
When you are with your favourite mates of all time. CAN NOT BE USED WITH UNGENUINE MATES. Use it when you pick up the phone to your mate, all your favourite mates are in the same place, when your mate does/says something to do with an inside joke.
1. Brit/Aus colloq. A female friend, a gal pal, etc, usually fairly attractive, that is part of your otherwise male 'crew' or mates, but generates no sexual interest or feelings from either you or your other male friends of that group as they seem to be just accepted as one of the guys.
2. A girl you are friends with but, due to not being able to take the relationship further, reaffirm to yourself as only a friend and/or even outwardly advise as such to people who inquire as your relationship.
John: "Wow, that chick standing over there having a laugh with your mates is pretty hot. I guess you'd like to do her, eh?"
Jack: "Nah, she's a chick-mate. It'd be, y'know, like, doing one of the guys... yech!"