Looking for a yaoi/shounen-ai. The manga was relatively new (translated in the last two years or so) and had clean art.
I only remember events of first chapter.

Plot: The school is having a festival and everyone is helping out. The uke was in the store room (or maybe gym room) and likes to cross dress so he puts on a wig (not sure) and lipstick and looks in the mirror and smiles at himself because he thinks he's looking cute. The seme is sporty type and was helping clean up after festival. The seme catches him doing that and later confronts him saying he's weird for cross dressing and smiling at himself. He said something like "you were definitely smiling at yourself".
They had never talked before this incident and the uke was worried that the seme would blackmail him the next day.

I might've gotten some details wrong but this is the general summary for chapter 1.
Also I'm using seme and uke but it could've just been a shounen-ai as I didn't get to read the whole manga.

Thank you in advance.

Based on how it starts (a guy looking himself in the mirror thinking he's cute and stuff), it might be Houkago Edge. There's no school festival, though.

Other mangas in the same line and that have a school festival:

Sekai de Ichiban Hageshii Ai no Ippou Tsuukou!
Himitsu ni shiro yo!!

You can also take a look to the titles under the Cross-dressing category and Shounen-Ai genre, and to the Cross-dressing and Yaoi genre.

If the manga is 2 years old you can check the ones that has been published between 2015-2017 and that had been translated. I think you'll find it in any of those two links of above.

Good luck!

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That's the one I was re-reading when the story came in my mind.
Sorry it's not one of those you mentioned but I appreciate it . I've also skimmed through the lists multiple times and none seems to fit the bill.
A part of me thinks that maybe my mind played tricks on me and is confusing more than one stories but another part wants to believe it's an indivudal manga.
After wracking my brain, I remembered reading the first couple of chapters of Seinen wa Ai o Kou a few months ago and it has the school festival scene, a sporty straight seme and a scene where the uke puts on lipstick. In this particular manga, the uke hated cross dressing and himself when he put makeup on.
I think this manga is where I got the idea of a cross dressing-sports festival and sporty seme.

Then I remembered reading the first chap of Kono Koi ni Mirai wa nai and in this one the MC thought of himself as beautiful when putting on make up....and he was looking in a mirror.
So prolly this is the one where I get that mirror idea from.

Then finally Houkago edge is probably the one where I got the idea of the uke thinking he'd get blackmailed the next day at school after the seme saw him.

So, this makes me believe I was mixing all these manga. (Tho I'd love if it was a real manga....maybe it is but I can't tell for sure.)
Thanks a lot @Bog Initiate for taking your time and replying. Really appreciate it

Oh, that's typical. It's very common to mix stories in our minds when we have read a lot of them in a row and/or when they share a similar theme.

It's nice to know you were able to figure some of the titles that composed your 'fake' memory
Anyway, maybe, in the future, someone would publish a manga like the one you have in mind. As far as I could check in the lists I suggested you, I noticed that there are many with school festivals, sporty semes, or ukes that think they're cute themselves, so, it's possible. Haha! XD

So happy to help you!

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Yes, I often tend to mix stories up but not as bad as in thinking it was an original manga lol.
I'll be reading from the list too and yes maybe one day someone might publishe a story like this.
Have a lovely day!