If Genos knew he'd be sitting in between two men, acting as a heater for long hours, he honestly would have taken on the call for a hero in C-City. He was certain that, had he muscles, they would be in intense pain from how long he had been sitting there, immobile.
To his left, Saitama was reading a manga, while under a blanket and huddled up beside him. Genos didn't dare try to move him. To his right was someone he honestly didn't expect to be there. A villain, who goes by the name Speed O Sound Sonic, and self-proclaimed rival of Saitama. Genos hadn't spent much time around Sonic, but heard a bit about him. He was fast, and for some reason, currently sitting in the house of his 'rival', hugging Genos' arm and possibly sleeping. He couldn't really tell.
It started when Genos woke up that morning to snow covering everything. He was quite surprised, as it was the middle of spring and normally it didn't snow in spring. Even Saitama, who wasn't much for emotions, was shocked. Mainly because his favourite store, which was meant to have a sale that day, was shut due to excessive snow. It was still an emotion. To make matters worse (for Saitama), his heater broke, and he just couldn't seem to keep warm in the 10 jackets he wore. Then, he noticed Genos still wearing his regular sleeveless jumper.
"Genos? Aren't you cold?"
Genos turned to his mentor.
"I have an in-built heating system." Saitama's face lit up and stared at him with a strange hungry kind of look. Genos felt his cheeks growing ever so slightly warmer. He wasn't even aware that could happen.
"S-sensei?" He asked.

The next thing he knew, he was on the couch and Saitama was in his lap. They had a blanket wrapped around the both of them, to keep the heat in. Saitama was watching the morning news report, as per daily routine. Genos face had most definitely heated up considerably. He'd have to check back with the good doctor soon to see if maybe somehow something was wrong with him? He wasn't sure.
"Maybe I could carry you on my back when I do my run later." Saitama murmured to himself. Genos shook his head.
"I would advise against that, sensei. However, I would be willing to run beside you."
Saitama sighed. "That's not gonna be much help. Oh well. Guess I'll just have to wear an extra coat." He stayed silent for a moment. "I wonder if we have any heat packs."
No sooner had he said this, the window opened and Sonic was just suddenly standing in front of them. He started off with a large, weird grin on his face and opened his mouth to say something, but then he noticed properly how the two heroes were sitting, and his expression changed to that of surprise or confusion, and his cheeks became the colour of ripe tomatoes.
"W-whats going on here!?" He demanded.
Saitama looked up at the villain.
"Oh, Panic. I'm just using Genos as a heater. You can join us if you like. You don't look very warm in those clothes." He said, then moved his head to the side, trying to see around Sonic. "Also you're blocking the tv."
Genos didn't bother protesting to Saitama's offer. He could see the ninja shaking, and his teeth were chattering. What would he expect, when he was only wearing a t-shirt and shorts. Sonic wrapped his arms around himself and lifted his head in a stubborn manner.
"I'm here to f-fight you, not get c-cosy with you! And my name is Sonic!" He stuttered. Saitama merely lifted one side of the blanket, letting some heat escape and brush past Sonic.
In an instant, Sonic joined the heroes under the blanket. And here they were, in different positions, but still huddling up to Genos for warmth. The sudden snowstorm was caused by some otherworldly monster that apparently really liked the cold. It was expected to all melt by the next morning.

"Is he asleep?" Saitama asked, leaning over Genos to inspect Sonic closer. Genos nodded slightly.
"I believe so. He has been this way for a while now. His grip on my arm hasn't loosened up at all however, so I wasn't entirely sure." Saitama hummed softly to himself.
"Probably time we got some sleep, I think."
"But, sensei. Were you not planning on going for a run?"
Saitama thought about this for a moment.
"I'll run twice as much tomorrow, it's too cold out right now."
Genos smiled gently at his master.
"As expected of you, sensei. So incredible."
Saitama shrugged.
"It's nothing. Come on, we better get this guy to bed before his muscles hurt in all the wrong ways." He rolled his neck before standing, bringing the blanket with him. He turned to Genos.
"I'll leave him in your care. G'night." He said, before promptly going to the bedroom.
Genos turned to the sleeping ninja at his side. His mouth was open slightly and was that drool dribbling out of the corner of his mouth? He wasn't quite sure, but he also wasn't about to find out. Instead, he gently tried to pry Sonic off of his arm, who only tightened his grip. He continued trying, but Sonic just wouldn't budge.
Finally, he heard a soft groan from the smaller man, and he was released as Sonic turned to his side, his back now facing Genos. Genos wasted no time in standing and lifting the ninja into his arms, cradling him close to his chest for continuous warmth, then made his way to the bedroom. The futons were set up close together, and Saitama was already curled up in one. He motioned for Genos to lay Sonic on the other, then told him to lay in the middle.
"This way, everyone is warm." Saitama concluded. Genos agreed it was the best idea, and would have applauded his master for his genius, if his hands weren't full of sleeping ninja. He softly placed said ninja in his designated spot, and lay in his own. Instantly, both Saitama and Sonic latched themselves to his arms, and he was immobile once more.
Sonic nuzzled his face against Genos' neck, which once again caused his face to heat up. He still wasn't completely sure if the ninja was actually asleep. Saitama bid them both goodnight, and placed a soft, sweet kiss on Genos' cheek, before also placing his face against Genos' neck. Genos found himself utterly speechless as the two slept at his sides, and his face continued to burn.
Though it was nothing like fighting some giant monster, in a heroic fashion, he still felt somewhat like a hero in this moment. Even with his strange burning face and even stranger sleeping positions. He was still a hero, just of a different kind.
And he wasn't regretting not taking that hero call anymore.