tattoo idea

To cross one's fingers is a hand gesture commonly used to to implore God for protection, as well as to wish for good luck.
The gesture is referred to by the common expression "keeping one's fingers crossed" or just "fingers crossed" and has also been historically used in order to allow believers to recognize one another during times of persecution.
Some people, mostly children, also use the gesture to excuse their telling of a white lie. This may have its roots in the belief that the power of the Christian cross might save one from being sent to hell for telling a lie.
A similar belief is that crossing one's fingers invalidates a promise being made.