Arf and Woof are covered in hair. Of course. They're dogs. And you've heard me rant about dog hair enough on here.
Both have black downy undercoats, as if someone covered them with tiny little black cotton balls. There's no difference between dogs on this undercoat.
The difference is in their top coats.
Arf's hair is short and stiff, like two-inch long bristles. Black on the bottom, silver at the ends. Spiky, although the hairs lay flat on his body.
Woof's is long and silky. Wavy. People often say he's the softest dog they've ever petted.
Everything we touch feels different. Remember haunted houses and feeling the olive eyeballs and spaghetti guts?
How things feel when our characters touch them is one way to use the sense of touch in our writing.
Another way is how touching makes the character feel.
A mosquito bite itches. When we scratch the itch, it's soothing. But scratch too hard, break the skin, and the bite stings and burns.
Think massage. I'd love one right now after Thanksgiving! Heavenly. The wonderful relaxation that comes over you when knotted muscles become unkinked. But sometimes those fingers and elbows hit that certain spot that brings a tiny jolt.
Our characters don't go through their stories without touching and being touched. Let your readers feel what they're touching. And let the character's experience being touched.
Your story will be richer and more vivid.