Now, since clutching relied on breaking up the other team into smaller, killable chunks, anti clutching will obviously be focused on sticking together.
An example of what not to do, from a scrim I played yesterday:
On contra, we rushed b and took the site, but everyone died but gambino. 1v4, he killed a guy coming from plank, had 2 seconds to turn around and kill another guy coming from spawn, had enough time to plant the bomb, kill a guy darkroom, and then finally kill another guy coming from plank. See the problem? They came at him one at a time, because they wanted the kill and assumed they would win because it was 1v4. Until the round is over, never assume that it is yours. Instead of being the hero, wait for your team. If 2 guys had come out plank while 1 came from spawn and 1 came from darkroom, all at the same time, he would have been shot from 4 different directions, and it would have been impossible for him to win.
Your goal should be to put your opponents in impossible situations. Another example of an impossible situation would be 1v3 with the bomb planted outside on train, and one guy hiding heaven, one guy hiding in ivy, and one guy hiding in connector. If non of them peak, the counter terrorist does not have time to find and kill them all, while still having enough time to defuse the bomb. You can only force impossible situations when there is a tight time limit.
If it is a 2v1, 2 counter terrorists not knowing where the last terrorist with the bomb is, you have two options. One is to play one person per site. If you choose to do this, then both players must play it passive or the must both hide in their sites. You should either be playing so far away that it would be hard for the terrorist to kill you before your teammate rotates over (an example would be playing from ct connector on de_cbble, watching B) or, play in a hiding spot inside the site that will allow you to peak the terrorist when he plants. The first option is better against better players, because they will tend to check all the hiding spots (possibly pre firing them) before planting the bomb. When attempting to play passively, it is vital that you do not try to engage the enemy without your teammate - your sole purpose is to get a faster rotate to the site that the terrorist is planting at.
Your other option with a 2-to-1 advantage is to both play the same site. This is preferable when the sites are close together, such as on de_nuke. Sticking together like this can be advantageous, however it can get you in trouble if the sites have a lot of hiding spots. In most cases, I would recommend both players playing the same site, to avoid splitting their resources.
If you have a 3-1 advantage, you would probably be best served by having 1 person play a site either passively or hiding, and the other 2 players working together at the other site.
If the bomb is planted and counter terrorists are rotating to kill the last terrorist, the counter terrorists have a much greater chance of winning if they work together. Unless there is very little time left on the bomb timer, no counter terrorist should be entering the site without the whole team. Once inside the site, your plan of action depends on how much time you have and how many hiding spots there are. The more hiding spots with a view of the bomb, the more you should have everyone search for the last terrorist. If there are not many avenues of attack for the terrorist, then one person should defuse while the other people watch possible peak spots. If there is not much time left, and you can't cover the defuser, you can try to shield him with your body. This only works if they have 1-2 seconds left on the defuse, and the terrorist is not close. If they are close, or there is too much time, you will end up both dying. You can also try having two people 'defusing' at the same time. If the bomb is planted in such a way that you can either defuse it out in the open, or behind cover that would force the terrorist to come to you, have one person start defusing under cover, while the other person pretends to be defusing out in the open. The terrorist peaks the first person, kills them, and assumes that he stopped the defuse, allowing the second person to finish. Only attempt this in the rarest of cases - you are sacrificing a player in order to win the round, when you could have saved his gun and possible killed the terrorist.
The key to not getting clutched is playing so that you can cover your teammates at all times. You should not be standing right next to them, because that allows one good spray to take both of you out. You should play so that you can watch one spot, while being able to quickly turn and crossfire with your teammate. Proper teamwork and an understanding of what makes you vulnerable to losing those types of rounds, is enough to stop most people from clutching. Do not get overconfident, because that is the quickest way to lose rounds.