This is an interesting question as I have never heard of anyone making this gesture. I have to say that I do not believe this is a common white (or otherwise) practice. I have never seen anyone do this, and have never done this myself.
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Name : Layla H., Gender : F, Sexual Orientation : Straight, Race : White/Caucasian, Religion : Christian, Age : 26, City : Evansville, State : IN, Country : United States, Occupation : Student, Education level : 4 Years of College, Social class : Upper middle class,