Getting your revenge in first.
Do unto him before he can do unto you, if you like.
A guy looks at you nastily across a rugbyscrum; next maul, you tear his ear off, before he does the same, or worse, to you. You have completed pretaliation. Anything he does after that is retaliation, which referees always come down on harder than on the original malefactor.
"Did you see Tonto get his pretaliation in on that mean-looking winger?"
"Yeah, he'll be counting his ribs for a month! What a kick! Bet Tonto keeps out of his way for the rest of the game, though!"
When you know you're going have a ridiculous amount of alcohol over the weekend and you decide to go out for a few drinks the night before as preparation - it's the drinking equivalent of stretching.
"It's the stag do this weekend, the pretox will be in the local from 7 tonight"
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.