The exhaust fan in the bathroom had never worked particularly well, so Iruka had long been in the habit of escaping that steam-filled room as soon as possible after a shower. During the winter he would usually stay long enough to don his bathrobe, but this was summer, and one of the hottest days of the year. So he didn't hesitate to leave the bathroom in nothing but a towel and escape to the bedroom, where a couple of open windows at least provided something of a cross-breeze.
He dropped the towel he had been using on his hair as he left the bathroom, flinching as the wet strands fell against his neck and clung to his cheeks. He grabbed a hair tie off of the dresser and quickly crossed the room to the full-length mirror on the closet door. First things first: get the hair out of the way.
He was just gathering his hair into its habitual ponytail when movement caught his eye. He turned away from the mirror and to the window behind him, but whatever it was was now gone. With a shrug he turned back to what he was doing, while still keeping a surreptitious eye on that spot in the mirror.
When he caught the movement again he didn't react, just kept working on his hair. He had to press his lips tightly together to prevent a smile when he saw a few spikes of silver-white hair come slowly into view beyond the frame of the window. He finished wrapping the tie around his hair before deliberately moving away from the mirror, loosening the towel as he did
“You don't need to spy on me, you know,” he said out loud, certain that his words would reach their intended hearer. “And it's not like you haven't seen it all before.”
There was a brief gust of displaced of air behind Iruka and Kakashi was there, leaning against the windowsill. “Maa, sensei, I was just practicing surveillance techniques. Have to keep those skills sharp.”
Iruka snorted. “Normally I'd applaud anyone's efforts at keeping up with their training, but you forget that I know you.” He crossed the room to where his clothes rested on the bed. He picked up his hitai-ate and reached up to tie it around his head, knowing that the movement of his arms would loosen his towel a bit more, causing it to slip further down his hips.
And it worked like a charm. Kakashi, although maintaining his usual appearance of bored indolence, looked anything but. His eyes had widened almost imperceptibly and the color in his face was suddenly heightened. Iruka turned to face him, slipping his thumb under the knot in the towel and smiling lasciviously as he took two steps toward his lover. “Is being surveilled all I'm going to get out of this experience?” he whispered.
Kakashi's long arms shot out and wrapped around Iruka, tugging the other man close. “Not on your life,” he growled as their lips came together and the towel finally gave up the fight.