It sounds like they're created separate from your limbs. But that might mean you could wield a separate weapon/shield with your normal hands while lashing away?
Specifically. I'm curious if they can be used by a Kitsune in Fox Form.
They don't use a physical hand.
"one or two lashes of ectoplasm tethered to her by wispy, ectoplasmic tendrils". Tendril: A slender threadlike appendage of a climbing plant. So, the lashes have their own appendages.
Ooo you could make that spooky water bender from Avatar legend of Korra.