Fic idea:
Where Yuma comes from, Trion sharing could be considered an intimate act, depending on the circumstances, almost like a claim or a marriage. However, on the battlefield, it's nothing more than to pick a comrade up.
So when Osamu suddenly asks him to share trion, he's flushed and embarrassed, telling Osamu that he pretty much asked Yuma for his hand in marriage.
Embarrassed, Osamu waves him off, telling him it's for training purposes.
But it slowly becomes a habit, sharing Trion together.
Till it becomes a thing they do, a unconscious habit, unaware that Trion sharing also ties to compatibility with your partner.
The stronger the feelings, the stronger the sensations, till it sometimes feel like their love sick fools.
Shivering at their first transfer, Osamu telling Yuma how cold it feels. Yuma laughing. "I don't produce much body heat."
Till every touch of their pinkies, Trion transfered, mingled, till it became a warm stream of comfort, safeness and a sense of selfless.
If Osamu had to describe Yuma's Trion is was, independent, strong, protective, and so, so warm.
Till pinkies weren't enough,to yumas feet sitting in Osamus lap, face shoved in his phone, mindless scrolling, only to focus on the sensation of Trion flowing through his legs.
Hes always felt the engery of his own Trion that hasn't stopped flowing for years but this, this was different. He'd never be able to explain it. It's was just so,,,Osamu.
Yet, neither have them have realized it runned deeper than the Trion.
But when their teams get mingled for the away missions, forced away from each other for 2 weeks in the first phase of the testing, why is that feeling still there?
When they haven't seen, heard or touched each other in 2 week?
And why, does his own Trion feel so..lonely?