Sentence:  This goes on and on: as long as you are asking questions, a <WSD>toggler</WSD> will toggle. (Keep in mind that on being asked a question the first time, a <WSD>toggler</WSD> will randomly choose to tell the truth or to lie). 
Meaning of the word marked with <WSD> tags:  Something that toggles between two states or causes something else to toggle between two states.