Both he and Lucy jumped (although he was less startled by the glass's violent arrival and more by the fact that he hadn't heard the person coming at all), causing whatever he was about to say to rapidly flee his mind as he started to glare at the interrupter, only to stop half-way through.
Oh, this was just peachy.
"Mira! Don't scare us like that!" Lucy whined slightly, laying her arms out on the table as her head plopped itself shakily down as well in relief. Mirajane's form hinted at none of the violence that she had exhibited just a second before, her face awash in a deep smile and her hand that had smashed the drink now up to her lips in a playful sort of way. Personally, Cobra often wondered which one he had to worry about more; the fiery hammer wielding red-head, or the demon matchmaker with way too much time on her hands?
Ideally, he wouldn't have to ever deal with either of them, but life has never been kind to him, so why start now?
"Oops! Sorry, that it was a bit too forceful. I got a little carried away there."