The very first thing I liked about the Drunk Elephant T.L.C. Happi Scalp Scrub ($36) is that it's applied when your hair is dry, not wet. Because of this, I was able to apply the scrub before I got in the shower and wait the 10 minutes on my couch, all comfy in my robe (which was more pleasant than shivering in the shower for 10 minutes after I wet my hair).
Plus, the multitasker in me could also see this scrub working well if I put it on in the bath, shaved my legs, and then stood up to rinse it out in the shower.