[Quick transmigration + period settings + no fixed couple + her personal space is for her use only; she can't share it with anyone or let anyone discover it.]
Xiuxiu is born to be the female lead's foil. Her name is simple, with none of the deeper meaning behind the female lead's name. By sheer luck, she awakens and gains the ability to transmigrate to other worlds as the female lead's foil, though she also faces various restrictions.
1. In the interstellar world, her fertility rating is zero.
The female lead is her sister-in-law. After marrying into the family, she has triplets, then quadruplets, then quintuplets.
Bound by her restrictions, Xiuxiu marries and has no children at all. But children aren't a necessity.
2. In the modern world, she's the biological daughter everyone despises.
The female lead is the beloved adopted daughter, pampered so much she never has to lift a finger, a little princess in everyone's eyes.
Xiuxiu is the biological daughter, disliked by everyone. But she doesn't care for their affection; she's her own queen.
3. In ancient times, she's the younger sister whose marriage is swapped.
The female lead is the elder sister. She marries a scholar and stays by his side until he becomes the top scholar.
Xiuxiu is the younger sister. She marries a concubine-born son of a marquis and lives in luxury, amassing a fortune. Better to enjoy life than suffer hardship.
The plot was good, but it made me anxious to death. Facing other people's provocations, I never felt pain or itching. I watched the heroine feel so aggrieved. Those people kept jumping around and even danced in front of the heroine with their faces wide open. Although the heroine fought back, it still felt weird and uncomfortable.