Nowadays used in a passive aggressive way (usually by the british) at school or somewhere public when someone tries to act big and bad or naughty when they're really just a try hard.
For example:
Person 1: Talk shit about me one time and I'll batter you - you hear me?
Person 2: Ooh, sorry roadman - I'm so scared - shiver me timbers!
A phrase used in a south park episode where Mr. or Ms. Garrison explored being a lesbian. Garrison was in bed with another woman "scissoring" (in which two women inter-lock each others legs for sexual arrousal). it is at this time that Garrison becomes excited and says "Oh yeah scissor me timbers!!!".
Lesbian: "I haven't gotten a piece of ass in a while I really wish somebody would scissor me timbers."