Twist and Babs met when they were in their late teens and Twist got her hair ruined, so she went to the nearest hairdressers (Which was Babs) to get it fixed. While in the chair, Twist would tell Babs how some bullies had ruined her hair, and before she knew it Babs was marching off to stand up for her and scared off the bullies. The two became fast friends after that and eventually started dating. Then Equestria went to war. Twist, tired of being bullied and always having to rely on Babs to fight her battles for her, joined the army and was stationed with Pipsqueak near the boarder. Due to overcrowding Twist and Pip were put in the same tent. Over the next year and a half they worked together in the field and got to know each other. Twist saved Pip's live a few time and Pip did the same for her and eventually Pip found himself falling for her and Twist found herself torn between her feelings for Babs and the new budding feelings for Pip. Eventually after she started her second tour, Twist told Babs that she loved her, but there was a stallion in love with her, and she was falling for him, and she didn't know what to do. Babs took some time and then told Twist she would be willing to try and make a heard relationship with Pip work.
After telling Pip about it, the base Twist and Pip were in was ambushed. After some fighting, the enemy would retreated, but both Pipsqueak and Babs were injured. Pipsqueak was injured from saving some wounded ponies from being attacked, and Twist was injured trying to save Pip and the rest of the ponies. They both ended up with lots of wounds, scars and burns from it. Pip also got heavy damage on one of his eyes, and Twist ended up losing the front part of one of her front hooves (She now has a prosthetic replacement for it).
They would both get medals for their actions, and would both be sent home. After meeting Babs, they settled into a happy relationship, and where then married a year later.
Pipsqueak is now a high ranking member of Princess Luna's Navy, and Twist now serves as a martial arts and self defense instructor, along with helping Babs in her shop. They also have 5 kids.
Twisted Seeds: Daughter of Babs and Twist, Twisted is the third oldest of the trio's children. Twisted is a cross species geneticist, working with creating new hybrid plants.
Sea Legs: Song of Babs and Twist, Sea Legs is the second oldest. He followed after Pip, joining the Navy as soon as he could.
Pip-ermeant Appleseed: Daughter of Pip and Twist, She's actually the oldest child. She took after Babs, becoming a tattoo artist.
Sugar: Daughter of Babs and Pip, she's the youngest alongside her twin, Spice. She loves baking with her sister and making sweets like Twist.
Spice: Daughter of Babs and Pip, the older of the twins, Spice love to bake and try new flavor combinations. Sometimes it works out, sometimes it doesn't but she doesn't mind. It's all fun for her.
Thanks to Ice1517 for the pairing idea and the backstory!
Ponies belong to Hasbro!