The trick or prank is meant as an illusion, since a person cannot easily observe the status of their own nose.
[1] Typically, the performing 'thief' of the act puts the knuckles of the index and middle fingers on either side of a child's nose.
[2] The hand position used when stealing a nose is also known as the fig sign, which can be viewed as an offensive or obscene gesture in certain cultures[7] such as in Japan, where it refers to copulation,[8] or Turkey, where it is the local version of the Western "middle finger" gesture.
This game is commonly played between children, as well as between adults (e.g. parents, grandparents, uncles) and their young relatives.
For instance in France, it is known as je t'ai volé [or piqué] ton nez !