The idiom "bumping heads" refers to a situation where there is conflict or disagreement between two or more people. Conversely, the antonyms for this phrase would be cooperation, agreement or unity. When people work together harmoniously, they are said to be in sync, collaborating or cooperating seamlessly. They work together towards a common goal, using their skills and knowledge to achieve success. In contrast, conflicts can arise when there is a clash of ideas or differing opinions. This can lead to tense situations and an inability to work effectively. Therefore, it is important to encourage teamwork, promote communication and foster a spirit of understanding to avoid situations where heads are constantly bumping.