Momo's Big Crush
 

Izuku would be training hard with one for all when Momo walks by though he doesn't notice her being too hard at work with training

As Momo watched Izuku train up his quirk, she couldn't help but be impressed. Deku was someone who clearly had a great amount of strength and power, yet he was also deeply insecure about himself, she could tell. So, it was then that Yaoyorozu came up with a plan, one that would both get Midoriya to come out of his shell as well as make him hers. Now determined to set this plan into motion, she went off to get the supplies that she'd need.

After a while the greenette has finished training and is heading to the showers to bathe

Momo discreetly followed him into the showers, with a bag slung over her shoulder. As soon as she manages to catch up to the boy she speaks up in order to get his attention. "Hey Deku" The One For All user turns around in shock, having been surprised by Yaoyorozu's presence and confused as to what she was doing there. "I saw you training earlier today, you looked great! In fact, I came up with this great idea that I think will really help you out in the long-term." It was then that Momo reached into the bag and pulled out a thick, white diaper, one that was Izuku's size. It was clear what she planned to do with them.

"Um. I'm sorry Yaoyorozu-san but I have to shower and get back to training can we talk later?" The greenette moves her hand off his shoulder and turns to continue walking to the shower

As soon as Midoriya began walking away, however, he's stopped by Yaoyorozu grabbing his hand. "I apologize for this, Izuku, but you don't really have a choice on the matter." Momo picks up Deku with a surprising amount of strength and lays him down on his back. Before he can try to get up and run she's strapped him down to the floor with some leather straps she had made using her Quirk. Then she once again picked up the diaper, preparing to tape it up around Midoriya's waist.

"What are you doing Momo-san?! What if someone sees?!"

"If they see then they see. It's probably something you should be getting used to, anyway." And with that statement, Momo lifted up Izuku's legs and slid the diaper underneath his rear. When she lowered them back down both her and Midoriya were quick to notice how his waist was slightly elevated due to the sheer thickness of the diaper. To finish things up she folded it up between and around his legs and taped it shut, firmly sealing him within the padding. Looking over Deku now that he was naked in nothing but a diaper, she realized how absolutely adorable he was in that state.

She would also see his many scars from damage done to his body due to use of his quirk without proper control or taking it too far more specifically the large scar on his bicep as well as the scarring around his fingers

Having finished taping the diaper onto Izuku, Momo finally un-strapped him and then pulled him into a deep hug, with his diapered bottom resting on her lap and his face being shoved straight into her breasts. She gave his rear a few pats, taking in the moment as best she could. So far the experiment had more than lived up to her expectations.