Alexis laughed with him, unaware that what he was laughing at was her. "Ah, it shouldn't be too hard with a little bit of this—" she then fluttered her lashes and did a kissy face as Dimitri had done earlier.
( He's actually laughing at what she'd said. Hence his statement. He's not mean like that. )
"Oh, very nice. Much better then my earlier rendition by far." Dimitri said good-naturedly. He was thoroughly enjoying himself.