Brian O'Driscoll (along with Rhys Priestland) explained a move - the wrap around - which he and Jonny Sexton utilised a great deal during their time as teammates with province and country. BOD showed the importance of getting close to the defender before playing the pass, so the opposition player is taken out of the game.
O'Driscoll gave the lesson on BT Sport's Rugby Tonight. He also went through what you're looking to do when defending a last minute drop goal like Ian Keatley put over for Munster on Saturday.