Not gonna lie, I find this arc boring which is why I don't feel motivated to continue writing at the moment and can't come up with good scenarios so sorry if updates are extremely slow or the scenarios are just boring.

Izuku Midoriya:

It's one of his favorite things as his muscles tend to be tense or hurt after using his Quirk too much. He will be embarrassed as you massage him, hoping he isn't being a bother to you or making you feel forced to do this. But when you assure him you don't mind, he will hum and give a little nod with a blush on his face.

Katsuki Bakugo:

He will be relaxed against you, you being the only person who will ever be allowed to do this, while rambling to you about the idiots in his class or how annoying the teachers are.

Shoto Todoroki:

He will be confused as to why you are massaging him but let you do it. He will relax into your hands. He was unsure how to feel about this. It felt nice but also not so he decided maybe he just has to get used to it and let you continue while frowning sometimes when it felt weird.

Ochaco Uraraka:

Her face will be bright red the whole time, nervously stuttering out stuff while flinching whenever you squeezed or moved your hand, letting out nervous chuckles while hoping she doesn't look like a complete fool.

Tenya Iida:

When you massage his legs, he's very thankful, saying this feels nice and thanking you for doing this. He will chuckle and say he might have overdone it again but doing so resulted in winning so it's okay and he can withstand the side effects of it.

Eijiro Kirishima:

He loves it. After using his Quirk, his body is always sore so when you give him a massage afterwards, he will be so happy and relieved, feeling as if he could melt. Once you are finished, he will chuckle and thank you, saying he really needed that.

Tsuyu Asui:

She got a small blush, not having expected this sudden massage. When you asked if you should stop, she shook her head and said it's okay, she just didn't expect it. So as you massaged her, she tried to think of what to talk about.

Momo Yaoyorozu:

She was feeling nervous and shy, her face heating up. She assured you she has a masseuse for this so you don't have to go out your way to do this. When you said you want to do this though, she gave a nod and let you continue.

Denki Kaminari:

He got so nervous that he accidentally electricuted you. It wasn't a lot, just a sudden spark that made you flinch and yelp. He was quick to apologize a lot while saying he didn't mean for it to happen and walking away from you so he doesn't do it again.

Kyoka Jiro:

She groaned as her muscles were tense so this felt nice, thanking you for it. She felt her face heat up a bit but she wasn't sure why because she didn't really find this awkward or embarrassing, she guesses it was just because you were touching her so much and she's not really used to that.

Fumikage Tokoyami:

He let out a "euhm...", not sure what you are doing or why before he asked you what you are doing. When you told him giving him a massage, he gave you a "yes, I know" before saying he meant why are you giving him a massage. So as you told him you just felt like doing it, he stared before humming and just letting you be.

Mina Ashido:

She will cheer, saying she likes massages. As you gave it, she excitedly told you about some stuff while patting a different spot and asking if you can also massage her there. When you finished giving it, she said she wants to give you one now.

Yuga Aoyama:

He stretched with a relaxed sigh, saying this feels good and he has been meaning to get a massage for a while now as all this training has made his muscles so tense. When you pressed too hard, he let out a yelp before telling you not to be so rough.

Eri:

She doesn't like it, it's too much touching for her and she's not sure what you are doing and it just makes her feel nervous. She just needs to get used to people touching her and squeezing her limbs without a bad intention, maybe then she might enjoy it, but for now, she rather has that you don't do that.