Scalp Only Wash Tutorial

How do you wash your scalp, but keep your length dry? This is how I do it! :) See my cool race shirt? Yeah, I did that race at 37w pregnant, just ten days before giving birth. Yup, it was 750 yards swimming, 12.5 miles bike, and 3.1 miles running (but I looked more like an elephant lumbering through, ha!).