I really like the Bill Malone cards across trick and I've done it befor. When I do it however, I'm always nervous about palming the 3 extra cards. This is why I don't perform the trick too often (if at all). How do I get over the feeling of having the palmed cards in my hand for such a long period of time? Is there anything in my practicing, I can do to get over that feeling?
Thanks for your information,
Bob

You could play around with palming 3 cards off the deck and then offer the deck to be shuffled before performing any of yor other card tricks that don't require a palm just to get the flight time in regards practicing it.

Here's a tip that many magicians have used to get use to palming....and not feel guilty.
Palm 3 cards....and walk around during the day during your normal routine. Whether on a bus, shopping, walking around with people etc. Eventually you'll become very comfortable palming and realize that no one sees it or notices it if you don't draw attention and act natural with it.

So now I have another question about this trick. What do you do or say when someone calls you out because when the packet of cards is in there hands they can feel they are missing 3 cards or have 3 extra?

This is very unlikely to happen, as a lot of participants do not handle cards that often to feel the difference in detail.

However, there are certain ways to prevent that from happening or/and to make you feel safe:
1) Audience management: pick the right participants
2) Control the participants actions and thoughts: Distract the participant with a question, a story, general patter. Don't allow to even think of that possibility of feeling the cards
3) If you structure the counting process well, there is no reason to question the number of cards that are being held.
4) In the end, if the participant really feels the change. That is exactly what you want, as it could be interpreted as the magical phenomenon you were trying to show them. You just have to frame it that way and control the timing

Just go out there and do it and get caught. Learn what exactly got you caught and stop doing that.

Keep doing that until you’re not getting caught.

Oh and you will get caught. Get over it.

What Danny said. Plus keep the routine moving. Make sure the spectators are engaged and watching what you want them to watch.

I have recently been using the gambler's cop to steal 5 cards from the bottom of the deck and handing the deck to be shuffled. This move once seemed so scary to me but so far no one suspects a thing. No one is even looking at my hands while the spectator shuffles.