It started a few months prior. Work had made them go home later and wake up earlier each day. On one such night, both of them completely exhausted - having run all over the city after a wayward NEXT with super high-speed as power - they had crashed to Barnaby's place. He had been way too tired to drive his partner home. Kotetsu could have gone home on foot for all he cared but no, he had followed him into his flat.
Not speaking a word, muscles already starting to ache, they threw themselves on the bed, instantly falling asleep.

The next morning, they woke up next to each other, face pressed into the mattress. Barnaby sluggishly lifted himself and sat on his heels, sleep still fogging his mind. His glasses were askew, ready to fall off at any moment. Kotetsu didn't so much as turn his head towards his bedmate, looking up at him in muddled wonder. Barnaby weakly glared at him, annoyed to see him first thing in the morning. At least, he hadn't said anything yet, which he was perfectly fine with.
The older man kept staring, then turned his upper body on its side and rested his cheek on his left hand, as if getting comfortable to continue his examination. Awareness finally settling in, he extended a hand towards Barnaby's face, plucking the dangling glasses off his nose. The blond didn't do much apart from scowling, still gazing down at his partner.

A shrill sound coming from their wrists distracted them from each other. They had a mission. Eyes met, both men nodded their mutual thought of 'Let's go'. Glasses quickly returned to their rightful place as the bed was suddenly empty, the frontdoor closing shut.

-T&B-

The second time it happened, they slept at Kotetsu's. The bank-robbery they stopped had been near his house. Fatigue had motivated them enough to drive as less as possible, which got them in Kotetsu's living room, eating dinner with a rediffusion of their arrest on TV. Dinner finished, they took turns for the shower, Barnaby going first. The older male lent him clothes and gave him a towel, absently watching the television. When Barnaby stepped out of the bathroom, he asked where he was going to sleep. Kotetsu, not really paying attention, vaguely motioned for his own bedroom as he undressed for his shower.

Entering his bedroom, he found Barnaby fast asleep. Not wanting him to wake up, he tip-toed his way to the unoccupied side of the bed before sliding underneath the cover, instantly falling asleep lulled by the blond's quiet breathing.

During the night, they had somehow gravitated towards each other. Kotetsu was on his back with an armful of Barnaby who had his head pressed to his chest, the top of it tucked under the older man's chin. Their legs fared no better : Barnaby was nearly entirely in Kotetsu's lap, his thigh pressing between the other man's, unconsciously rubbing calves with his partner.
Kotetsu woke up to a ticklish feeling on his neck and shoulder. Half-asleep, he swatted at whatever it was that teased his skin to highly irritating degrees. His relief didn't even last a second as the thing instantly came back, just like a spring. Scrunching his nose and frowning, he repeated the operation a few more times before giving up.
Sleep was ready to claim him once more when something shifted on his chest, moving the thing to tickle the side of his face. Aggravated, he suddenly noticed that the shift had extended itself to his entire left side - which was warm for some reason other than the cover - and even placed what felt like a hand on his right pectoral.

Hand?

Kotetsu groggily opened his eyes. Wincing at the sudden light, he caught sight of the thing tickling him, or more exactly, Barnaby's hair. The kid had curled up, head digging deeper into his tan chest. Remembering last night, he lightly tapped the blond man's shoulder. If he didn't get up now, Kotetsu might do something drastic. Like cut his hair - or chewing them off since he didn't have any sharp object near him. When all he did was stir a bit, the older man did it three more times before his partner picked himself up, yawned and rubbed sleep out of his eyes with his thumb and forefinger.
They were in the process of getting out of bed when twin high-pitched sounds resonated in the room.

Quickly dressing, they went back to their hero lives.