I shampoo obsessively because I'm addicted to tingly shampoos. I use Paul Mitchell Tea tree,Gueye stimulating shampoo, and Profectiv anti-damage shampoo is a great detangler. I clarify with Kenra or Nexxus Aloe Rid.
A co-wash is washing the hair with conditioner and not with shampoo, I think because its more moisturizing and gentle on the hair?? That part I am not sure about.