Sorry about the bad word people say that Remus was the boring Marauder. he might've been the responsible one, but he most definitely could keep up with the others in trouble-making, or even be better than them sometimes.
Pretty sure James would say himself as a joke and then say Sirius because let's face it, those two are practically married. Peter would say it because he looked up to him (until Voldemort). Lupin might actually say Sirius though.
I bet that James flew out there on broom in the middle of night because he had a bet a day before with some Ravenclaw (who happened to be dating Lily at the time, but shhh, that's not important, Moony!
One time at school James looks under Sirius's bed and screams out loud--"Sirius, there's a big scary one down there he's got fangs and claws and I think his fangs are venomous!" and Sirius goes to look and it's Remus just like, "Hey, what's up?
In the meantime sirius beaks into the great hall yelling and all you know is that theres a lot of cheering, betting money being handed over and people giving him their congratulations. *bonus* confused AF first years