I'm sorry: this is a very *basic* question, I've tried many many times before posting here, but I've always failed
I'm not sure that "dribbling" is the right term, so I'll try to explain what I can not do (and it should be easy!).
Starting with the deck in the dealing position on the left hand, I'd like to get the deck with the right hand dropping the cards fluently while lifting it, one card by one. What happens every time I try is that the first cards drop one by one, then the cards start to fall in small groups together. What is very annoying to me is that I think this is a very basic action. I can do "harder" things but I can't do this simple one
If you have ever seen the Daryl's sleight videos, my dribbling is just like his one when he says: "not like this"!!!
So, any advice is welcome (where to put fingertips, how to bend the cards, everything).
Thanks.

I just take the deck in Biddle grip (from above in my LH) and use my LH 1st finger to apply slight pressure to the centre of the top card. This will cause a convex bend and should help you to dribble the cards more evenly. Then try to run your fingers and thumb up the narrow sides as evenly as possible.

Gio...

Try dribbling the cards in the fashion mentioned below, and see if this will work for you:

As the RH is placed over the deck to take it, grab it with your left thumb at the back, and the middle, ring, and pinky fingers at the front. The index finger should be curled slightly on top of the deck.

Slightly squeeze the deck between your thumb and last three fingers, as you take the deck out of the left hand. This will put a very slight bend in the deck. Remember to keep your index finger curled on the top of the deck.

Now, let the back end of the cards spring off your thumb, and the front ends of the cards will follow. The ends of the deck should be bending upward, as your curled index finger keeps slight pressure of the bend.

Depending on how fast you allow the cards to spring from your thumb, will determine how quickly the cards will dribble into the palm of your left hand. Start with just half a deck, and once you get the 'mechanics' down, add the rest of the deck, and practice with the full deck.

Hope This Helps,
- - Troy

Thank you very much guys - I can dribble cards now

My two main problems were:
- not keeping the index finger until the end (I slightly bent the card using the index finger but I did not keep the pressure with it)
- putting too much pressure between my thumb and the fingers on the other (short) side of the deck

Practicing with half deck really helped to understand my mistakes.

Gio