well I don't think he laugh at him because he was flabby xd I think it was for his intent to hide it, 'cause he wasn't expecting that. It also make me laugh a bit, not with evil :P >///<
I think it was just the situation that made his partner laugh. It wasn't like he was overweight or anything he just had no muscle tone and was a little "flabby". I would have laughed too if my partner tried to suck in their stomach to hide what I already knew was there, and at that moment was just situation funny.
Trust me, when your partner do that during that kind of situation, you will end up laughing.....x'D so funny xD
urm when he noticed he was flabby n stuff I felt so sad for him, if my partner laughed at me for that i'd just slap him :) Lol ^^ Laughing at people is so mean D'=