Bubble play in a NLHE tourney:
When you have a big chip stack (big = five or more times the average at the table, IMO; 10xaverage would be better), you can play the table bully. But if there is another stack that is greater than yours, be careful. You do not want to find yourself in a war with that guy -- you are just looking to steal blinds and antes from the medium stacks and the small stacks that are hoping to squeak past the bubble. You want to be pushing at people who are worried and who can't really hurt you.
Since the blinds and antes at this point are usually pretty nice, if the other players don't play back at you, you can amass a substantial increase of your chip stack. But DO NOT FORGET WHAT YOU ARE DOING. If a very small stack shoves his 3BB stack, it's OK to stay in that hand. If he wins, it does not damage your stack much. But if a 15BB stack shoves, you want to have a hand of some sort. Otherwise, you are likely to whittle down your own nice stack until you are also in trouble. (Been there, done that.)
If at all possible, do not engage with other big stacks. If one of them is trying to be table bully, then you may have to back off on that job. Unless, of course, you find yourself with a monster. Even then, consider whether this is the time you want to go out. (Yes, you could double up. But when there's a bigstack war at a table, they both usually have very nice hands. And I can't tell you how happy the other players are to see this battle. I'm not saying fold your KK--but be ready to be OK if it loses. It's a choice you make, so no crying.)
Some bigstack table bullies will raise every single hand. That creates an interesting psycho-social dynamic. People start to resent it, they get angry, and some will get up the courage to call or shove. Some of them will double up, which will give others the courage. Especially if you call a shove with garbage and they see it. So I advise not raising every hand. Behave as if you are using some sense. Conversely, it's not necessary to wait for a premium hand. That is wasting an opportunity.