wait for it
1. Do not continue or begin (speaking, moving, doing something, etc.) until precisely the right moment. Don't start the attack until you see the signal from our scouting party. Wait for it… OK, go now!
2. An interjection used parenthetically to indicate that the speaker is about to say or introduce something one thinks is particularly funny, interesting, exciting, or surprising. So while we were out on our date, we got talking about our families, and it turns out that he—wait for it—is a distant cousin! I couldn't believe it! So a horse goes into a bar, and the bartender says to him—wait for it—"Why the long face?" Get it?