[It takes Robert a few seconds to gather his semi-sleepy (due to the stroking) consciousness to a point where he can formulate a response to that. But it's such an obvious thing, now that he thinks about it - Don doesn't have anything like hair, and so it would obviously be as foreign to him as having scutes and keratin plating was to Robert.]

Well, in the case of hominids, hair is generally meant to serve as a form of protection from the elements, and provide some sort of sensory input... mostly in the form of being able to tell when it is moved. The hair strand itself is, as you likely already know, insensate and technically dead; the root of the hair is the living, growing part, and it is the part which is ennervated.

For example, I can feel you moving my hair as a mass, but were you to bend a single hair in on itself, it would not cause me pain. [Robert smiles reassuringly.] Now, attempting to pull it out of my head most certainly would...

... As for what having it is like... [Robert hums thoughtfully.] It's certainly much more pliant than scales, and while cleaning it can be a bother, it does provide one's cranium with some protection from the direct elements.

... One can also do interesting things with hair if one is so inclined, but I've never found myself to be the hair stylist sort.

[At least that's one gay stereotype nobody can accuse Robert of having?]