When someone says something to a member of their sexually preferred sex that is so obviously flirting. when this happens, anyone around that person normally shouts out BC.
The announcement of BC can often lead to cock blocking.
Example 1:
Guy: you look amazing (to a girl)
Mates: BC!!BC!!
Example 2:
Friend 1: (insert name) is so hot!
Friend 2: I think you should try it on.
Friend 1: I'm going to lay down a cheeky BC.
BC this is short for batty Crease. This is shorten so u can put it on the end of texts or emails to ppl who u believe to be a batty crease but dont really want them to know. People will often see it and take no notice that they have been insulted. It is a very effective way of taking to piss out of someone without them knowing.
Text: Safe yeah,
hopefully i will see u soon but i am not sure i have alot going on with my amazing life