To add flavor and moisture to meats or other raw ingredients, you can soak them for a while in a flavored liquid marinade (note that the word for the liquid is spelled with a D). You marinate it (note that the word for the action is spelled with a T). You would rarely have a legitimate reason to use the phrase “marinate on.” An example would be: “leave the chicken to marinate on the counter while you prepare the other ingredients.”
When you ponder a subject thoughtfully, you meditate on it. So many people are misusing “marinate” when they mean “meditate” that some have concluded that they are related words with overlapping meanings. They urge people to think carefully about a subject by telling them to “marinate and meditate” on it. Letting thoughts soak into your consciousness has nothing to do with marinades.