"Finally?! You mean you..." you can't wrap your brain around what you're hearing, what you're seeing. It makes no sense, not one lick of it. People don't just turn into birds. It doesn't work like that. Maybe you were hallucinating. Yeah, that's it, you're hallucinating. Or this is all just a bad dream.
Normally watching your girlfriend completely disrobe was a fascinating, glorious experience. But as you watch her take her pants off to reveal a backside that is looking less and less human and more and more bird, you can only feel dread and horror.
"Would you shut up and relax already? You freakin' out like this is only making the change harder for you, clearly," she asks, exasperated with you. Her hair... her hair is falling out. That beautiful, glorious hair is just dropping off of her head like it was never rooted in to begin with. She suddenly turns around to face you, her eyes further apart than normal, her mouth stretched and distended.
"We should do it. One last time, before we change. Just in case we're not the same species of bird," she says with a manic, excited grin.
"W... we should?"
"Totally! I don't want to go into the rest of our lives and never be able to make love again if we didn't try one last time," she grins, and her arms begin to fold in to her chest - like bird wings.
"I... I..."