Sneak Attack

One of the boys' favorite games to play is "Sneak Attack" when I am preparing dinner. Since there are two ways to get into the kitchen, they go back and forth between the two attempting to be quiet in between their giggles. Joseph doesn't know how to be quiet and quick...or he doesn't care...so he is always my clue as to which side they are hiding.

They will throw "bombs" in my direction to lure me out of the kitchen, when they will run passed me and grab a piece of whatever veggie I'm preparing. My first reaction was one of displeasure naturally. Until I realized that Joseph would be eating items I had attempted to feed him for meals. I then began using this game to my advantage, not theirs...until Joseph beat me at my own game.
Now, instead of sneaking the healthy options, I hear Joe imploring Jacob, "Come on Jacob, let's sneak the candy."

Their new goal is to sneak beyond my sight into the pantry and climb up the shelves to reach the bag of Dum-Dum's originally meant for Joe's potty-training reward.
Evidence in each of their bedrooms suggests that they have been successful in their endeavors (hopefully when I was in another room. I can't be that detached).

If I happen to turn around and catch them in the act, Jacob will be quick to run away. Joseph, on the other hand, will stand there in a duel, fists clinched around his prize.
"Joseph, what are you doing?"
"Me? Just only nothing."
"Joseph, what is in your hand?"
"Just only nothing, Momma...don't look with your face. Just go fix dinner."

And now, whenever Joe is busy minding his own business, playing on his own, and Jacob wants him to play "Sneak Attack" or do something else that I suspect would receive disapproval, Jacob pries, "Come on, Russell it up."

I'm not sure what the term "Russell it up" means, but I'm scared.