This scene takes place when the 'adventure arc' is starting to veer into more psychotic territory, the humor getting into South Park territory in terms of breaks from reality.
Calvin having a conversation with Rosalyn talking about how much he hates his foster father, Thomas.
Calvin (angry): And he's always insulting me...
We abruptly jump to a different scene with Calvin sitting on the couch in his home, watching TV. Thomas steps in with a bag of Taco Bell, he gruffly throws the burrito at Calvin, hitting him in the face.
Calvin (squinting as he's opens the burrito): Thanks...
Thomas grabs his own burrito and takes a seat on the couch next to Calvin, eating it as he watches the TV.
Calvin (taking a bite): You got back fast.
Thomas (casually): Yeah well, time flies when you're a faggot...
Calvin stops mid-bite and just stares up (at the TV and camera and audience) in irritation.
We then cut back where we left off with Calvin mid-conversation with Rosalyn.
Calvin (getting angrier): ...it doesn't even make sense half the time!