#Also I know very well B is pronounced as V in Cyrillic so Rush B doesn't work

[da-riya]

Unfortunately, as much as it would make sense, "Rush B" has nothing to do with the fact that the Russian "В" means "In". In reality, it came purely because Counter Strike Source was, and still is, MONSTROUSLY popular in Russia and so it just kinda... got into the lexicon.

Брате(( Это была шутка... (Excuse my bad Russian)

Like, CS 1.6 was crazy popular here as well! We just called it Кантер and it basically came with every single PC including the informatiks computers at school. During Highschool my whole classroom had 15 minute matches during brakes (and sometimes they'd extend during class)