Flandre made a little grumbling sound of protest when Remilia brought up the Sentinels--and obliquely all the other times she'd been shot. But:

"I will, Remi." At least she would do her best to try.

Putting her wings on was always a bit of an odd experience. It felt like there was something stabbing into her spine without any pain, before the sensation disappeared--even when Flandre thought about it. When the wing secured into place, the crystals hummed slightly as they lit up, channeling excess energy away from Flandre. She stretched the wing a little, though not too much; it wouldn't do to hit her sister in the face.