He shifts to sit up, separating much of their points of contact enough for Istredd to notice before he is thumping down on top of Istredd, his arms folded and expecting to catch Istredd's eyes when the movement no doubt takes the actual wind out of him. If it works, Istredd will see him grinning down.

Serious topic? Yes. But Lucifer's exceptionally good at being the one to hide and close off. Step back. He would maybe even let Istredd do it if he wasn't already still the equivalent of a caveperson.

Also Lucifer is feeling good, physically and mentally. It isn't often he can share and offer that.

"So you were going to do what I did and bottle it up. I'm not sure if anyone's bothered to tell you, but taking emotional pointers from me is unwise."

Keeping his arms crossed atop Istredd, he pokes a finger between his ribs. There is no real reason for this other than some strange way of his to keep Istredd from sinking into his head.

"I know where you and Yennefer stand, to at least some degree. In this hypothetical scenario of yours: you knew nothing about Kyle and I." He draws out, almost a song, "Which makes... your feelings... ?"

Valid. The answer is 'valid', Istredd.