Being Open
The first time Yukina managed to convince Kisa to pick him up at T University from an evening class, Yukina's friends noticed Yukina was sparkling a lot. He didn't actually do that in class or when he was around them, except if he was doing a presentation or trying to ingratiate himself with someone. So the fact that he had such a blinding aura about him threw them off and they didn't even notice Kisa.
The second time, they did notice Kisa. However, he and Yukina left fairly quickly so they never got approach him.
So, the next day during a break between classes they had together, Yukina's friends decided to approach.
"Who's that kid who keeps coming to see you?" one asked as they sat on the edge of a large planter, drinking canned green tea and covered in paint.
"Kid?" Yukina asked, not immediately thinking of Kisa. Perhaps his friends had noticed one of the girls from the bookstore who sometimes came to see him when they found out he was a student there.
"The one you always leave with."
Yukina's face lit up. "Ah, you mean Kisa-san."
"I guess," his friend said, waving his hand like the guy's name wasn't important. "Is he your brother or something?"
"Ah, no. Kisa-san is my boyfriend."
At that Yukina's friend started choking on the green tea he'd been gulping down, and he took great, gasping breaths, trying to compose himself. "That kid is your boyfriend?"
"He's not a kid. In fact Kisa-san is older than us," Yukina said, as if that was the issue.
He watched with concern as his friend just stood up, grumbling, "He's gay and he still gets more girls than I do. How is that fair?" before he walked away.