Knocking on wood (also phrased touching wood) is an apotropaic tradition of literally touching, tapping, or knocking on wood, or merely stating that one is doing or intending to do so, in order to avoid "tempting fate" after making a favorable prediction or boast, or a declaration concerning one's own death or another unfavorable situation. Origin A common explanation traces the phenomenon to ancient Celtic peoples, who believed it called on spirits or gods of the trees, while Christians tie the practice to the wood of the cross of crucifixion. A more modern theory from folklore researcher Steve Roud suggests it derives from a form of tag called "Tiggy Touchwood" in which players are safe from being tagged if they are touching wood. The British version of the phrase "touch wood" has been traced back as far as the 17th century. Similar traditions across the world In Bosnia and Herzegovina, Croatia, Montenegro and Serbia there is also the habit of knocking on wood when saying something positive or affirmative about someone or something and not wanting that to change. Frequently the movement of knocking on nearby wood is followed by / ("I will knock on wood"), or sometimes by / ("I don't want to jinx it"). In Brazil and Portugal, ("knock on wood") is something actually done physically, three knocks are required after giving an example of a bad thing eventually happening. No verbalization is required, just the three knocks on the closest piece or object of wood. In the absence of wood, someone can say , to prevent the bad thing to happen. People do not actually believe knocking three times on a piece of wood will really protect them, but it is a social habit and it is polite to do so to demonstrate that one doesn't want that bad thing one is talking about to actually happen. In Bulgaria the superstition of "knock on wood" ( ) is reserved for protection against the evil, and is not typically used for attracting good luck. Usually people engage in the practice in reaction to bad news, actual or merely imagined. In most cases the nearest wooden object is used (in some areas, however, tables are exempt); if there are no such objects within immediate reach, a common tongue-in-cheek practice is to knock on one's head. Knocking on wood is often followed by lightly pulling one's earlobe with the same