As he gets older, Genji’s body gets weaker, which makes him have to have his mask on more often. I would think that there’s some breather in there to help support his weaker respiratory/biological systems. 

They’re not big on sappy PDA, but they are big on physical contact. At any moment, they usually have a hand on the other or simply stand close to one another. 

Zenyatta has lots of nonverbal tells for his inner thinking: humming, head tilts, shifts in his orbs’ movement, etc. Genji unintentionally adopts some of these throughout their relationship. 

Zenyatta is really into Genji’s mouth and teeth. Genji is really into Zenyatta’s hands and back. 

Zenyatta tends to wear flowy clothes with windows/cuts (that thigh window or whatever in his aang skin got me in an aesthetic chokehold). I will draw him in shrugs and croptops once I can grasp fabrics again trust

Genji tends to wear simple, almost minimalist clothes on the daily, but you'll find him in something crazy if it's the right time. However for day-to-day, it's usually a variation of a white top, dark bottoms, and a hoodie.

They both have a ton of scars and scruffs from over the years. They find comfort/feel relaxed when the other traces along them.

Genji grew up with anger issues (runs in the family it seems), but he can manage them well now. One of his major issues was blurting out the first thing in his mind, no matter how hurtful or ignorant it was, so he has to pause and articulate in his head before speaking when he's extra pissy.

Genji likes to collect trinkets and keychains. If he has the space, he tends to arrange them into a battlefield on his desk.

The letter is an excerpt from an unfinished character study I wrote about Zenyatta. The context is that Genji and Zenyatta, while they're still only friends, send each other letters when Genji returns to Overwatch, usually with small gifts like a pen set that Zenyatta sent.

The journal is Genji's. I like thinking that he likes to journal, especially as a way to get his thoughts together. He'll write in the form of a letter, and if he feels like it, tear it out and send it.

The potted plant is a small hobby of Zenyatta's. While he spent time with Symmetra, he picked up her interest in nature (based on her skin and spray).

They share the bracelet, along with various other accessories. For bracelets and other small things, they might make it themselves and gift it.