verb/a.pɥi.je syʁ lə ʃɑ̃.pi.ɲɔ̃/
to step on it, to floor it, to put the pedal to the metal, to put one's foot down, to step on the gas
“Chauffeur, si t’es champion Appuie (× 2) Chauffeur, si t’es champion Appuie sur le champignon.”
Synonyms: mettre les gaz, mettre le pied au plancher
Literally, “to press on the mushroom”. The word champignon (“mushroom”) is slang for the accelerator pedal.