Using Duplicates

Hey everyone!

I've got a question for you all:

When I'm doing street magic, I usually link my Ambitious Card Routine with the French Kiss, but if I want to let spectators shuffle the deck before the Ambitious Card, I have to add the duplicates to the deck afterwards. What I do now is keep them in the card box, then put the deck away and bring it back out asking if they want to see another trick, but that method seems awkward and suspicious.

I guess the ideal way to add the gaffed card(s) would be to use a palm from the pocket, but I don't feel very confident with that technique, and I get the feeling it would be easy to get caught.

Could you guys share your methods and/or ideas on this??

Thanks so much!! 😋 😋