Time to go very still while his ears turn red. 

She buries her face in her palms. "You're both idiots... Do I want to know..."

"So there was this hunt, on Phoenix Mountain, and I decided to show off by using demonic cultivation to order all the ghouls on the mountain to go turn themselves in at the Jiang gate, while blindfolded, and then I relaxed in a tree, and while I couldn't see anything someone came up and stole my first kiss!" 

"Your first--"

"Pfft, did you believe all that bragging I did? Only you would."

She pokes her recently resurrected dad.

"What? I was absolutely ridiculous!"

Poke. "Be nice."

Pout. "Fine. My claims were absolutely ridiculous, but I was behaving even more outrageously than I usually do back then, so I suppose Lan Zhan can't be blamed for taking me seriously." 

She leans back, satisfied.

"I--even back then, I knew it was wrong." 

"Ah, I'm not exactly complaining. It's nice that I didn't die without ever having been kissed." 

"Ah, Lan Zhan. I didn't die on purpose. And I'm here now." 

HUG. 

Wow this actually feels really incredibly good and warm and safe. He is maybe going to curl up a little closer into Lan Zhan's embrace. 

Wow okay this is approximately the best thing that's happened EVER, Wei Ying is ALIVE and CUDDLING HIM and might even have feelings for him??? What even is this. Since when does Lan Wangji get to have things this nice happen to him. 

"...Do you guys want me to duck out?" she asks, quietly, feeling kinda awkward.

"I never want to make you feel unwelcome," he answers without even thinking about it. 

"Oh I don't feel unwelcome, just - you two seem like you'd like to make out and I would rather not be in the room."

"Oh. Uh, yes please." 

She smiles a little and heads out to find something else to do. Like maybe talk with Lan Jingyi...

And now they are alone together! Which...was the idea. So he probably shouldn't have butterflies in his stomach like this. 

Lan Wangji does not have butterflies in his stomach right now. Lan Wangji got those all out of the way when he was a flustered teenager who had no idea what to do about his feelings. Lan Wangji cradles Wei Ying to his chest with an awed reverence appropriate to the fact that his beloved was dead for thirteen years and now is alive and in his arms and this is precious beyond any measure.