@imaginaryxx73 okay sooo!! Here are some ideas on which you could create one shorts or series (I am not good at this):
1) yashiro went to minamoto house for sleepover and they all enjoyed tiara, kou and teru and at the night when kou and tiara were sleeping teru and yashiro talked (or you can use anything which comes to your imagination, mainly the preference is yashiro at a sleep over)
2) when yashiro was strangling akane in the "butterfly effect" Chapter of tbhk, you could use teru pov on that.
3) idk if it's possible but could you make like, a royalty au? As in nene being a commener Or a Duke hated daughter or something but she is actually very nice and ofc teru being the crown prince or something.
4) teru feeling jealous of yashiro hanging out with hanako and kou.
5) (at the trial with teru, tsukasa, hanako and baby yashiro) like yashiro confessing and teru getting irritated.
(you could make it kore fun by teru sending akane death glares that once this is over he is dead)
I can tell more if you want! I hope this helps