Synesthesia: the production of a sense impression relating to one sense or part of the body by stimulation of another sense or part of the body.
People who have synesthesia are basically experiencing life a thousand times better than the rest of us. They taste foods when they see colors, or they hear music when they smell flowers. The world itself is more complex and invigorating because the mind is combining two or more senses.
Ted-Ed Video on Synesthesia:
Writers can use the concept behind synesthesia to create multiple sensations related to their characters, settings, or emotions. Have a character that's not so nice? Describe him/her with words that invoke negative sensations, such as prickle, vinegar, or screech. For a main character or someone you want to the reader to like, use positive words like fleecy, coffee, or melodious.
Look back over your WIP. Are your word choices contributing to the overall sensations you are trying to accomplish? What pairings will help your reader better connect to your characters and story?