Ive written something interesting about the role of backup delay within counter-strike. A little basic, but its here to remind all those people, how to play a specific role. Just incase you forgot...

Backing up delay can be very very important at times within a clan game. It gives you the advantage of breaching with bigger numbers, and therefore having more chance of getting the bomb down quicker.

EG: When players: 1,2,3,4 is doing a top A rush on dust2, 5 is in the middle, while they are doing the top A the person in middle has to know when to flash (a lot of communication is required here due to the reason that you don't know exactly where they are and how close to breaching) the middle to stop the guys from B backing up the teamies at A and trying to hold them off for at least 5 seconds (while the opposite, breach)

He does this by means of flashing once, then waiting for another 4 seconds then flashing again and trying to delay by means of occupation (not trying to take the guy head on, but irritating him to remind him that you are still there)

The only time you move in and try take that guy head on, is once the team is in the site, the bomb is secured and they're in positions (at that time, the opposing player who you were irritating has no choice but to get to the site as the bomb is ticking down)