Did you know Grumpig's official Species name is "The Manipulator Pokemon" Many of it's pokedex entries talk about how it uses it psychic powers to control. I feel like this pose does a lot more to emphasis that, looking smug and reclining back on her tail like a seat and I added an extra pearl coiled within her tail cause I felt like I needed to fill extra space but also it works in relation to Spoink, where Spoink used to balance a pearl on it's head now Grumpig uses the Pearl as a counter weight to balance its body in the air.

I took inspiration from an outfit worn by Miss Piggy in Muppets Treasure Island, and the name is also inspired by Miss Piggy and her designer's name a Piggy Bank.
Miss Piggy's first name was originally Piggy Lee, a name given to her by Muppet designer Bonnie Erickson in 1974. The name was a joke and tribute to Peggy Lee, a jazz singer who was known for her independence like Miss Piggy. However as Piggy's fame grew, the name was shortened to Miss Piggy to avoid upsetting Miss Lee.

Madame Bonnie-Lee Bank takes after Miss Piggy in personality; She's a tempermental diva, very smug, quick tempered, violent, fiercely independent but enjoys romance. She would described herself a as flawless, one of a kind, once in a lifetime talent.
Perhaps in reference to her origin she also likes Jazz.