For a while now, Dave has been intending for the wires to cross here. He's not avoiding the introductions, it's just timing and indulgences that keep it from happening. When he's alone with Feferi, he isn't always thinking about his sister and when he's with Rose, he feels like he owes her a little more undivided attention.

Her voice is enough to have him relaxing and he nods when Feferi glances at him so she understands both the lack of threat and the fact that she's right here.

"Yep." He answers for her, clearing his throat before he steps forward and puts a hand on the small of Feferi's back. The gesture alone is probably symbolic of what she is to him, but he might as well explain. "This is my sister of technicality, Rose. Rose, this is my... uh. Gillfrond. Feferi." He knows he picked the word, but damn if he doesn't feel like a huge nerd using it sometimes.