Or is this the answer?
Makes sense she would wear it on her rear with wire up through her hair in the back.
Portable defibrillator.
That’s her tail.
The brain stimulation device wouldn’t be what’s under her Red outfit. But that’s not to say she doesn’t already have one of those implanted under her skin in her front shoulder pocket to hide her Parkinson’s or PSP symptoms.
The coaching device for her ear is a very real possibility. But only if she’s gotten the extreme mini-version that fits ALL the way into the ear canal so it can’t be seen without a doctor’s scope.
Another possibility for that bulge is an external drug pump with or without wireless remote controll. Whatever kind of “upper” she gets at Chelsea’s Emergency Room is what the drug pump would be filled with. Either levadopa or amphetimines would be my guess.