Being polite with both hands

I realized it in the bank, where I spent a good ten minutes watching Cartoon Network, while waiting to ask about their conversion rate, which was abominable - a pitiable 0.89625 dollar for a euro when in the street I would get 1 to 1 at least - that I have read that in Cambodia one gives and takes an item with both hands, that is polite. Completely unpractical, but polite, and I kept forgetting it. Also because I always have many other things in my hands, and because it's so foreign to me. The Cambodians who have seen enough tourists now, probably know that we have no clue and adjusted the gesture: they give you the whatever with one hand and with the other hand they touch the arm that is holding what they are giving you. Subtle, if you don't know, you won't notice, but they can still be polite - secretly.