Meredith Vieria stopped by the Tonight Show last night, and promised Jay Leno that her ongoing prank wars with Matt Lauer aren’t over. During a recent visit to the Today Show for a Rock Center promo, she lipstick-tagged Matt Lauer’s office mirror with some swear words. Lauer struck back: Once she returned home, Vieira opened up her purse to see a pair of bright white boxer briefs. But she’s sure they’re not his. “Normally he wears a thong,” she told Leno. “I can see the little panty line!” We can only imagine how Lauer will retaliate for the airing out his dirty laundry.