The phrase "spreading it on" typically means to spread or apply something generously, but there are several antonyms that describe the opposite behavior. "Holding back" is a common antonym, meaning to restrict or restrain from excessive expression or action. "Withholding" and "refraining" are also effective antonyms, indicating a conscious decision to avoid spreading something too widely or too quickly. Alternatively, "scrapping" or "abandoning" could be considered antonyms, meaning to stop spreading something altogether. Overall, these antonyms provide a range of options for describing behaviors that are opposite to "spreading it on," whether in terms of restraint, reluctance, or outright abandonment.