lunafish prompted me with Blaise/Millicent: nappies, mother-in-law, infidelity.
Just a Matter of Time (G; Blaise/Millicent, Mrs Zabini, implied OCs; 200 words): Blaise's mother overstays her welcome.
-act of infidelity! No Zabini wife ever birthed tri-"
Zahara is ranting again, and again, about her. Millicent can't help but hear her mother-in-law; she's shouting at Blaise just outside the nursery room door, and she has her hands full with the nappies.
She's rejected Zahara's offer of the "gift" of a house-elf. The woman cannot be trusted; there's no telling what one of her house-elves might do to the babies.
"-tested! They're not yours!"
Millicent prepares to Vanish Nappy the Third when an idea occurs to her. She places Baby Three-she and Blaise haven't yet decided upon their children's names because of Zahara's interference-into his cot and opens the door.
"Mother, I won't-"
Blaise sees her; Millicent presses a finger against her lips.
"-have you-"
"I'll say what I plea-agh!"
"How careless of me," says Millicent, after upending the contents of Three's nappy over Zahara. "But then, given the shit you're spewing, I suppose you won't mind wallowing in it."
"I'll kill you for-"
"No, you won't." Blaise draws his wand and presses it into Zahara's back. "Expello!"
Crack!
"You might Banished her before I started on the nappies," Millicent says.
"Yes, well, timing is everything," Blaise replies, grinning.