"I had some pretzels at the bar," was Sirius's protest. "I'm alright, I don't need anything." The expression on Tonks' face told him she wasn't going to budge. "C'mon!" he drawled, trying to make it into a joke, but realized she was steadfast. "Alright, cheeseburger it is." He looked around and spotted an empty booth nearby. "We can sit there."
As they walked over to the booth, Sirius stumbled and he almost fell; he thought that was hilarious and started cracking up. "Watch out!" he declared.