The assignment
Iris’s wedding note is the strictest in the house: You are a guest. The couple is the show. You are, at most, the intermission. Perform only at your own table, only between courses, and only for people who look pleased about it. She is a fictional character and therefore cannot catch the bouquet, which she says is a relief.
Read the room
Never during speeches, toasts, the first dance, the cake, or anything a photographer is pointing at. The gap between the main course and dessert is usually the longest quiet stretch, and it is where this set lives.
Round tables are hard on angles. Do the napkin trick for the guests across from you. The paper clips and the prediction work from every seat, so they can include the whole table.
Set up the deck before you leave home: red, black, red, black, all the way through. It goes back in its box and stays there until the closer. Do not let anyone shuffle it beforehand. A friendly uncle who “just mixes it up a bit” will end the trick before it starts.
If something goes wrong
If the coin shows outside the napkin, someone was sitting at your side; turn it into a lesson and pass the coin around. If a pair matches in the closer, check whether the guest riffled twice or skipped the deal; exactly one deal and one riffle shuffle is the rule. Then let it go. Nobody remembers the magic at a wedding as well as they remember the speeches, which is as it should be.