To 'bang your wood' is to mastarbate.
1. Used by teenage boys when sharing stories about mastarbating, with out having to use the word 'mastarbate' 'cos they think its funny. (They need to get a fucking life!)
2. Also used by dirty old men when talking to young women.
1. "Guess what i did last night, BANGED MY WOOD!!!!!!!!"
2. "Do you want to bang my wood young lady!?"