Define Crossed Fingers Meaning

it means being "one"; two become one as in two bodies become one in sexual intercourse; being one in mind and body and soul;
locked together as in coitus interruptus (sex).

The act of fingering, upon which she slides her fingers in, crossing them with yours to double the sensation.

Something you do when hoping for a favorable outcome. You want luck on your side.

an action performed:

1) for luck.

2) to exclude oneself from the rules which would normally apply.

3) to imply that "we're like *that*", ie as close to each other as two crossed fingers

Can be represented by the emoticon (yn); apparently this pictorially resembles crossed fingers ...

To try and test your luck

Refers to where you also manually cross your ring-finger over-top of "Big Boy", and then cross "Little Boy" over-top of your ring-finger; the theory is that perhaps this will give you a better chance of not getting your a** blown off than you'd have from crossing just your first two fingers. Extra points if you cross all four fingers of both your hands in this way, and/or if you also scuttle around and similarly-arrange da hand-appendages of any and all bystanders (provided their fingers are slender and limber enough to fairly-comfortably do so, of course) prior to saying, "Well --- here goes nuttin'"... with THAT voluminous number of "overlapped digits", it would conceivably put pressure on Fate to allow your endeavor to succeed, similar to how a prayer-chain supposedly does with God.

It's a saying said when you wish to wish good luck for something.