There is no particular idiom here, not in the version in the novel (a dumb rush of luck) nor on the tv (a rush of dumb luck)
Either way, the man is saying that the reason he is winning is just random (ie dumb) luck. And so the girl should roll the dice, since she is likely to win.
The present perfect is used as he is describing his current state. "Until now I have made many lucky rolls of the dice". (In fact I know from comments that he is cheating by using weighted dice, and she is a witch and is using magic...) Although we don't see it in the clip, we understand that Boris has been playing dice (and cheating, and winning) for a long time until now.
In craps, rolling 7 (or 11) is an immediate win. 2,3 or 12 is immediate loss. Otherwise you have to keep rolling the dice until you get 7 (and you lose) or you get the same number that you got on the first roll (and you win). The probability of winning is approximately 50%. However the game shown is "just roll 7" There is a 1/6 chance of getting seven, even with fair dice (and presumably much lower with Boris's loaded dice) so his claim "the odds favour you" is a lie.