A/N: I bet you all forgot about this!

Guess what? SO DID I!

(Christmas Eve: Class 1-A Common Room)

“Why am I doing this again?”

“Darling, you know why.”

Izuku sighed as Momo put the final Christmas lights in his hair. He was well aware that his hair somewhat (completely) represented a Christmas tree. It was Eri’s first Christmas and the adoptive parents had decided that they should start holiday traditions for Eri.

...Izuku being the tree wasn’t one of them. Momo just thought it would be cute.

Holiday traditions were something that families always looked forward to, and it was pretty clear at that point in their lives with Eri that they were a family. 

They had tried to establish a tradition of baking treats for everyone earlier, but Eri wasn’t comfortable enough around Sato yet and the parents weren’t confident enough with their baking skills to do it themselves. 

But, they had finally come up with the perfect idea. What did Eri love besides apples (and her Mama and Papa of course)?

"Kyouka, are you ready?"

The rocker in question stood in a Santa Claus dress with combat boots and fishnets, her arms crossed and her gaze piercing. "You both are so lucky that I'm a good aunt."

"I'll take that as a yes. I'll go grab Eri." Momo kissed Izuku's cheek and ran up the stairs. Izuku chuckled and turned to watch the snow come down outside. Christmas was a strange holiday for them to celebrate saying it's origin is based off of a religion not majorly practiced in Japan, but the meanings of family, generosity, love, and being together that the holiday had was something everyone could get behind. 

Christmas Eve was also meant to be a romantic day for couples in Japan. Izuku actually didn't even know that until that year. It was a piece of information that slipped under his radar due to his complete lack of romance in his life. 

However, with Momo and Eri's entry into his life the holiday had a greater purpose to him. He'd do anything for them. Like dress up like a Christmas tree, for instance. He knew Momo felt the same. But, having a child suddenly thrown into your life, no matter how much you love them, can disorient you for a bit. One's focus completely shifts towards the child.

Momo had been working 24/7 to make Christmas perfect for Eri. 95% of the decorations were hers. The common area looked like a winter wonderland because of her. Her devotion to Eri somehow made Izuku love her even more, and he had no idea how that was possible. Every action of love she made didn't go unnoticed.

So, it also didn't go unnoticed that she had forgotten to get Izuku a gift.

It wasn't that he cared. Material gifts were just that. Materials. All Izuku cared about was that Momo was safe and their love stood strong.

In fact, knowing that she didn't have the time to get Izuku a gift because she was so focused on Eri just made Izuku's gift to her even more justified in his mind.

"Papa!" Izuku turned around to see the Momo carrying Eri down the steps, both wearing holiday themed outfits. Eri was a Santa Claus sweater far too big for her, essentially covering her entire body. A matching Santa hat adorned her head, but with a small hole in the white fluff for her horn. Momo was wearing a dress with the same theme of Santa’s coat and a hat. Izuku smiled as the two made their way towards him.

 Momo squeezed Eri in a little hug, “Go ahead Eri."

"Oh, uh trick...or treat, right?"

"Wrong holiday."

"Oh, uh...Mazel Tov!"

"I-... close enough."

At least Hanukkah was in the same month...even if the phrase had nothing to do with the holiday. The rest of Class 1-A began entering the common area, and a small group joined Kyouka around a tarped object. A tradition that the whole class agreed to was an annual Christmas party. A fun tradition that would keep the class together for at the very least one day a year for the future.

Drinks and food began going around as the noise picked up from conversation. After a while, Momo gained everyone's attention by tapping her fork on her glass. "Everyone, I'd say our first annual party has been a great success. But, there's one more thing we'd like to do." 

At Momo's mark, Kyouka flung the tarps off of the objects at the front of the room, revealing the instruments from the Cultural Festival. Eri loved Kyouka's voice, and a mini concert was something she'd definitely look forward to every year.

The original band members all took their places, including Momo who gave Eri to Izuku to hold. Even Katsuki took his place at the drums and began playing classic, obnoxiously catchy Christmas tunes. As soon as Kyouka began to sing, Eri's smile was plastered onto her face. 

Kyouka would sing to Eri all the time, but they had never recreated her experience at the Cultural Festival. Even if this was on a smaller scale. And if they could do that every year, then the tradition was solidified.

 Eri didn't know many of the songs, but it was clear that she didn't care. She was unconsciously moving to the rhythm in Izuku's lap. Song after song, the concert eventually died down. It was time for Izuku to start his own tradition with Momo and begin their first gift giving as a couple. Izuku gave Eri to Kyouka, and the purplette began showing the little girl some bass riffs up close. 

Izuku pulled Momo from her keyboard and gestured towards the outside. They grabbed their coats and made their way towards the door.

…

Izuku and Momo walked outside in the snow, hands intertwined. They walked past Mineta, who was tied to a light pole with Christmas lights. One of the 1-A girls (who would remain anonymous so Aizawa couldn't punish her. *Cough* Kyouka *Cough*) had tied him up after he had walked around with a mistletoe hanging from his belt buckle.

"Merry Christmas, Mineta," the duo said, simultaneously.

"Merry Christmas guys. Do uh...you think you could get me down?"

Momo pursed her lips, "Kyouka specifically said you weren't allowed down until after the concert. And it'd probably be best not to cross her."

"Nah, I get it. Enjoy your evening." They nodded to the teen and continued their walk. The duo walked their way to the main archway in front of the dorm building, the moon high above them causing a shimmer to the snow.

Izuku stopped them and pulled out a small box, "Merry Christmas, Momo."

"Oh! Oh my goodness! I-...Izuku I-"

"Forgot. I know. Thank you."

Momo furrowed her brow in confusion. "Wh-? Why are you thanking me?"

"Because you didn't get me a gift, which you didn't have to do in the first place even though you would have anyway, because you wanted to give Eri the best first Christmas anyone could ever have. I would sacrifice every gift I'd ever had and ever will have for that." He looked down at his shuffling feet and continued. "I...I-I know I'm the reason you were thrown into being a parent. But, you didn't shy away. You immediately took Eri into your arms and loved her, and you still somehow manage to love me everyday. I don't deserve you."

"Izuku, you-

"No one deserves you. No one is worthy enough." Izuku interrupted, a smile slowly creeping up into his face. "But I'll never give you up. So I'll spend every day for the rest of my life being as close as I possibly can to be worthy of you. So, I'll start with this." Izuku gave her the small box and waited for her to open it.

With watery eyes, Momo unwrapped the gift to find a small black box. Her heart stopped as a small ring was placed inside. "Izuku! I-...This is-... We're not-"

"I-It's not a wedding ring! No! Not yet. I may love you completely, but we're only teenagers. It's a promise ring."

"Are you sure?"

"Momo, everyday I wake up I want nothing more than t-"

"No, I meant are you sure this is a promise ring?"

Izuku lifted a brow, "What?"

"Promise rings usually aren't this...extravagant. All of these diamonds and…Izuku, I think you accidentally bought an engagement ring."

"...So that's why it was 400,000 yen."

"How much?! How did you even afford this?!"

"I-I don't know! It was all so fast! I-I went out to the jewelry store with my mom and she helped me pick out the ring and...Oooooh."

 Damn parental meddling.

Momo couldn't help but laugh at Izuku's realization of what Inko had done. "It seems she's somehow even more eager than you to hear wedding bells."

Izuku rubbed the back of his head in embarrassment. "I-I'm sorry. I'll return it and get you a real promise ring."

Momo gazed back down at the ring and shook her head, "No."

"...Hm?"

"Well, how I see it, a promise ring is a sign that you promise to love someone forever and you'll never be apart. It's for people too young to marry. So, what's the difference between that and an engagement ring?"

"One means we're going to get married!"

Momo's blush deepened, "And do you think we won't one day?"

Izuku faltered, "I...Well I had planned on it, but...I mean...I guess it does mean the same thing to us."

Momo slid the ring onto her ring finger. "Then, I'd like to keep it. Perhaps get one for you. I'm paying this time." She cupped Izuku's face with both hands and his arms snaked their way around her waist. "Merry Christmas, Izuku. I love you."

"Merry Christmas, Momo. I love you, too." The two brought their lips together, the heat radiating off of the kiss canceling out the cold of the air. Soon, they made their way back inside, their future even brighter than before.

Mina also called them fiances for the rest of the night after she saw the ring.

...Not that they really minded.

A/N: This topic kinda stumped me. It switched from traditions to simple holiday romance.