I've proposed this on MS before, but I think self-defense is self-defeating. The more you talk about yourself, even to defend yourself from attacks from other players, the more you're centering the conversation on YOU. The game doesn't move on from the case on you unless you help move it that way, and if you keep providing more content on yourself, well.. it just gives people more you to talk about! In my opinion the best defense is a good offense.
This never stops me from talking about myself anyways because i'm a narcissist even when I get lynched for it..