Arya had been travelling with Sandor Clegane for a while and she did whatever she could to provoke or annoy him. So, when they made camp near a lake one day, she gave him a cocky look and said: „Maybe you should hop in and take a bath before they will be able to trace us by your stench." The Hound scowled at her but said nothing. That disappointed her greatly as she'd expected him to mock her for being a spoilt lady or something.
Sandor sat by the fire. Arya was asleep and he remembered what she had told him earlier. Maybe she was right, he thought, he hadn't had a bath in a long time and he was getting filthy even for his standards. He decided to take a quick bath while she was sleeping, so she at least wouldn't get the pleasure of seeing and making snippy remarks.
Arya opened her eyes. Sandor wasn't sitting by the fire, which was surprising. Then she heard footsteps. She sat up and saw him walking away, towards the lake. She grinned. So her words had made an impact after all. Yet, he might have been about to do something else than bathing, so she decided to see for herself. Very silently, she crept a few yards behind him, just far enough for him no to hear or spot her. When he reached the edge of the lake, she hid behind a particularly large tree and watched.
Sandor slowly removed his armour. His shirt and boots followed soon after, then his breeches and in the end he removed his smallclothes. He was turned towards the lake still, so all Arya could see was his back. Still, there was plenty to admire, she decided. The pale moonlight made all his scars visible and his back was marred with them, it was also was and looked strong. Her gaze dropped down to his calves and went back up to his muscular thighs, then even higher to size up his buttocks. She blushed and had to remind herself how much she hated the man, before she'd get inappropriate thoughts.
Then, in a surprisingly elegant motion, he jumped into the water. He looked amazing when he was swimming there, in the water lit by the moon. She could see every muscle of his large body moving and he moved with grace, surprising for such a big brute of a man. He swam to the middle of the lake. There seemed to be a shallow place, because he was suddenly standing, the water only halfway covering his chest. Finally he was facing the bank. The light of moon made even his burnt face somewhat comely, she thought.
Then he started washing himself. Face first, then neck and his long, powerful arms. When he smoothed his big hands over his broad chest, Arya found herself blushing even more than before and she desperately tried to shush the thoughts in her head, to no avail. His hands continued their journey lower and lower, painfully slow and Arya realised her breath was becoming shallow and she hated herself for it. She was glad she couldn't see what he was doing under the surface of the water even though she had to admit she was a little curious...
When he was finished, he swam back in the same fluid motion as before and then he started stepping out of the water. It was an even more enticing sight than when he was getting in. Slowly, the water released him and she could see his chest was covered in scars as well, but many of them were covered by thick, coarse dark hair. When the water descended below his waist, Arya could hardly hold back a gasp. He was a big man indeed. Her head was swarming with wild ideas and she decided it was time to head back to camp before she would be discovered. She really didn't want to know how the Hound would mock her if he knew she was watching and, what was even more embarrassing, enjoying the view a great deal.
Sandor stepped out of the cool water of the lake and lay down on the shore, letting his skin dry. And letting the little Stark girl get back to camp and pretend she was asleep the whole time when he got back.