no lo vuelvas a hacer

don't do it again

→ no
phrase Rare #37,919
don't do it again An informal command addressed to tú. The construction volver a + infinitive means “to do something again”; lo refers to the action or thing being discussed. Formal commands use no lo vuelva a hacer.
SP: ¡No lo vuelvas a hacer o tendrás problemas!
EN: Don't do it again or you'll be in trouble!