Humans are badly designed in general but kissing is good.

Those are both accurate statements! 

Leo is pretty pleased by the human invention of kissing! And frustrated by the concept of a refractory period.

Refractory periods are pretty frustrating, it's true. 

Fortunately lately for them both, they don't last forever, and Sasha is a sixteen year old boy so they dont even last very long. 

"I bet you could make me come lots."

"I wonder if you can come on command." 

"We should try it."

Sasha kisses him and says "Come. Now." It's the same voice he uses on Marlo when his shoulders get too-tight and what he needs is to go all soft and trembly. 

He was a little turned on before, turned on the way you're hungry when you're just starting to think that a meal would sound nice, and then Sasha says the words and a wave of absolute pleasure crashes through him and he comes and he's left trembling.

"Gorgeous." 

"Nnnnnnnng."

"You're beautiful and incredible and I love you." 

There should be kissing. Sasha should kiss him.

Sasha should kiss him. 

Sasha does not have even a little bit of his homework done the next day. 

Neither does Leo. Also, he gets distracted staring at Sasha and falls out of his chair.

"It went well, then?" Marlo says when he sees their faces. 

"Yeah," Sasha says, and kisses his cheek. "It went great." 

"What changed?"

He glances around; nobody seems to be paying them any attention but his face is still pink. "I — don't mind Sasha sleeping with people he's close to? But if it's casual it just makes me feel like I must not mean much." 

Sasha curls up halfway in his lap and puts his head on Marlo's shoulder. "You know that isn't true." 

"Course I do." A kiss on the side of Sasha's head. "But still." 

"...I guess it's different for me because I've known Sasha literally my entire life?"

"Yeah. And I've known him for most of mine, it's just — for us that's ten years." 

"I'm just saying that I wasn't ever casually into Sasha."

"He's trying to say that it felt different to him at first because you only came into our lives very recently for us, but the way we interact with each other is clearly not casual," Sasha says before Marlo can respond.