Peeta Mellark: District 12’s best liar.
After the Capitol party on the Victory Tour, I think Peeta was looking to stir up a little rebellion of his own, using his best weapons: his wits and his words. Katniss’ fake pregnancy probably got her some sponsors, but she really didn’t need the help. I prefer to think that Peeta was building on the agony and confusion the Capitol citizenry was already feeling about sending in their victors by creating a scenario that would cause the Capitol to rethink itself. Katniss fueled rebellion in the districts, but Peeta turned the Capitol upside down, and for his troubles, Snow tried to take his weapons away. Katniss was Snow’s intended victim, but you can be certain that he took great pleasure in scrambling Mellark’s brain.
Plus you know Peeta *totally* drew her naked.