Давать по рукам: to slap someone on the wrist, to punish
А ну-ка, давай вали отсюда! Get the Hell out of here! Get lost! Naff off!

      Russian and English are so rarely in sync that when you come across similar usage you want to kiss the dictionary. Take "давать/дать” (to give), for example: There are blessedly few problems, but of course there are a few traps for the unwary.
     "Можно давать совет, взятки, сдачи, деньги в долг”. (You can give advice, bribes, a beating or a loan.) It's also smooth sailing with a phrase like "Он даёт уроки английского” (He gives English lessons) or "Я дала ему 500 рублей за шкаф” (I paid him 500 rubles for the cupboard). "Ему дали три года условно” is reversed a bit in English, but still on the same wave length: He got three years probation.
      "Что дают?” is a bit more problematic. If said today, it means, "What are they giving out?" In a film about the Soviet period when someone asks it of a person lining up in front of a store, it means, "What's for sale?" Remember "дефицит” (deficit goods)? If there was something for sale, it was like a gift from the gods; who cared if you had to pay for it? 
      In other cases, "дать” can be rendered by "let": "Дай ему сказать!” (Let him speak!) "Они дали мне понять, что возьмут меня на работу”. (They let me know they'd hire me.).
      Then there's дать as "to hit," nicely like the English "to give it to someone." "Когда он стал меня оскорблять, я дал ему в морду”. (When he started to insult me, Igave him one right in the smacker.) Behind the beer hall you can also hear "давать ему в нюх/в пятак/промеж глаз/по рогам” (to hit him in the nose, right between the eyes, on the noggin, literally "on his horns"). Давать по мозгам (literally "to hit someone on the brains") and "давать по рукам” (literally "to slap someone on the wrist") mean "to punish": "Его жена дала ему по мозгам”. (His wife really gave it to him.) And "Я тебе дам!”, said in a threatening tone, means "You're gonna get it!"
      There are more useful forms of giving: "Пришлось дать ему на лапу”. (I had to grease his palm - that is, give a bribe.) Or the slangy "Мы дали сверху”. (We paid extra.)
      The all-purpose "давай” is one of the first words foreigners learn in Russian. We all know that давай + infinitive or future perfective means "Let's ... " Давай читать/почитаем книгу. (Let's read a book.) Or that "давай работай!” means "get to work!" Or that "давай” alone can be used as a sign of consent: "Хочешь пойти в кино?” - Давай. (Want to go to the movies? - Sure.) Or that it can even be used to mean "goodbye," perhaps once in the sense of "be on your way": "До свидания!” – "Давай!” (Bye! - See you!)
      But we foreigners overuse давай and sound like wild and crazy guys trying to be cool. I suspect the mistake is excessive use of the repeat form: Давай-давай! is a rough way of saying, "Get a move on it!"
      Be careful when давать is said of a woman; it means "to put out." Иногда легче дать, чем объяснить, почему ты не можешь. (Sometimes it's easier to put out than to explain why you can't.)
      Users beware: This is terribly crude - not to mention sexist - and should not be bandied about to impress your in-laws with your progress in idiomatic Russian. It's a kind of short form for отдаваться, "to give oneself" in the sense of "take me, I'm yours!" I'm not sure that anyone "puts out" or "surrenders themselves" anymore, but should the need arise, it's always nice to know how to describe what one is doing. 
      And besides, it's a reminder that it's more blessed to give than to receive. 

      But how can one say it in English with the tone of humor "Ну, вы, блин, даете!"? ...Russian is so insatiable about colloquialisms!