be on to a good thing

Từ điển tiếng Anh - Cambridge Advanced Learners Dictionary

be on to a good thing idiom
informal to have an easy and pleasant life or job in which it is not necessary to work hard
• He's on to a good thing, he has free accommodation in return for answering the phone when the family are out.
Thesaurus⁺: ↑Satisfied and complacent ↑Showing arrogance and conceit ↑Confidence and self-assurance
Main entry: thing_idiom