Antonyms for the phrase "with a kick" could include "lightly", "softly", "gently", or "calmly". These words convey a sense of delicacy and ease, which is in direct contrast to the forceful nature of a kick. Another antonym could be "unremarkably", which suggests a lack of notable or striking qualities. However, depending on the context, an opposing phrase might not be necessary. In certain situations, the phrase "with a kick" might simply be used as a description without needing an antonym. Ultimately, the antonym chosen will depend on the desired tone and meaning of the overall sentence.