The phrase "bust one's balls" is a vulgar expression that refers to someone putting in a lot of effort or working extremely hard, often to the point of exhaustion. However, there are many alternative and less offensive synonyms that can be substituted to convey the same meaning without resorting to crude language. For example, "working one's tail off," "burning the midnight oil," "toiling relentlessly," or "slogging away" are all suitable alternatives that are more professional and appropriate for use in both formal and informal settings. Choosing more tactful and respectful ways to express the same sentiments can help to avoid potential misunderstandings or offense to others.
