"It's the principle of the thing, you asshole," Lambert bites back, gesticulating with his sandwich. "How would you like it if someone--"

The thing about attempting to shove someone in the shoulder is that it usually goes over a lot better when they are, say, actually solid. As it is, when Lambert pushes out and puts his weight behind it, he nearly overbalances, because there isn't anything there.

It does also mean that his hand is now halfway through Tamaki's shoulder. Which he'll stare at, blankly, before delivering an eloquent:

"Oh for fuck's sake."