Short for iWillDestroyU, which is very fun to say in a deep voice to small children to scare them. Also sometimes short for i Would Do You and other fun sexual phrases ;) The "i" is lower case in reference to the very popular apple devices.
Boy texts to girl: "iWDU" meaning iWouldDoU. Girl text back "iWDU first" meaning iWillDestroyU first and take all your money and your car and crush you emotionally leaving you just an empty suicidal shell.
by Corona&Lime November 13, 2012