What causes your car not able to turn it off?

yesterday i turned my car on went to town.When i got there my car would not shut off the key wouldnt turn off.so i pushed key forward like i was gonna start it an turn back clockwise quick an it shut off.restarted it again an still wont let me turn the key to turn my car off. only way i can shut my car off is turn my key like im gonna start it quick an turn back clockwise ..this is hard on my starter.do i need a new key made or spray WD40 in the switch?anyone have any ideas for me?thanx..