Luffy was just walking around looking at everyone's awesome costumes while eating food. Granted his costume (http://i294.photobucket.com/albums/mm102/letjes/LuffyAfro.png) included boxing gloves, which made it a little more difficult to eat, but hell if he was gonna let that stop him. He noticed Raenef fumbling with his costume all the time and got curious as to why he needed to all the time. Have a Luffy looking over in your direction.