Loki almost, almost warns him not to take the drink lightly, again. Thor's ability to out-eat and out-drink even other gods is legendary, but Loki has a talent for processing alcohol, himself. It has to do with the Jotun blood and immunity to poisons.

So part of him doesn't appreciate the implication that he's a lightweight. They both know he's not...but why should he put up a fuss? That's counterproductive.

"Only two," he confirms with a smirk. "I suppose you think you can do better?"

Oh god. Is this going to turn into a drinking contest?