Buddying is a tactic used to subconsciously become perceived as less of a threat by another player. While this is usually done by scum, Townies have been known to do this as well.
This is typically accomplished by the buddying player acting unnaturally friendly to its target, either subtly or outright. Originally, this made it so that once the buddying scum died, it implicated the victim they were acting friendly toward. In addition, by budding up to a victim, they will become less likely to want to vote out the buddying player in the first place. More recently, though, this has become used as a pre-emptive accusation against anyone who acts nicely toward another player, regardless of intent.
Buddying is also known as Pocketing.