“Get off Me” is a phrase that originated from playing competitive sports video games. Whenever somebody makes a really impressive move on another player playing defense in the game, that person would yell “Get off Me”. It is a form of talking trash.
when there's someone on your boat that there shouldn't be, the only logical course of action is to don an Irish accent and attempt to reason with them, asking them to get off your boat. If this fails you must get your Jamaican friend and force them off your boat.