gone to plaid
When something moves entirely too fast (reference from Spaceballs) especially in the case of a relationship.
Joe - Hey did you hear Ken and Sue are engaged already?
Mike - But they just met last week!
Joe - I know, they've totally gone to plaid.
Mike - But they just met last week!
Joe - I know, they've totally gone to plaid.
gone plaid
Reached a state of babbling incoherence, rambling random, absurd gibberish. Origin: Spaceballs
By that point, he had long since gone plaid, and had no idea what he was trying to say.