“I want to thank everybody who’s here for the incredible warmth of the reception," Obama said at the event. "A sign of the warmth is the lipstick on my collar."
The president identified the "culprit" as the aunt of "American Idol" contestant Jessica Sanchez.
"Where is she? Auntie, right there. Look at this. Look at this. I just want everybody to witness," Obama joked.
“I do not want to get in trouble with Michelle, so I’m calling you out right in front of everybody,” he said.