I really like the second idea there. Would you want to roleplay/talk more about it?
The man and his wife have this self bondage escalation going on. She knows when he's coming home, she prepare herself, bound in a way that she knows she can't escape by herself.
The maid could discover by chance in several ways: she happen to watch the wife bound, she manages to watch while the helpless woman is blindfolded and unaware. Or it happens that the husband can't come home, so the bound woman is forced to call for help, or maybe the maid searches for her when she doesn't see her around.
Anyway the lady isn't so embarrassed because she's used to get 100% compliance from the maid. She just explains what she's doing and asks for help, offering a bonus because this is not one of the maid's ordinary tasks.
The maid is obedient, but she's a cool, detached woman, not submissive at all. She ties the lady of the house as she's ordered. Then, knowing that the husbands wants new surprises, she starts giving suggestions. This she does because she's having fun tormenting her mistress.
The lady is intrigued. She buys more toys, at the maid's suggestion, then she stops giving orders, leaving the maid to devise more and more ideas. The entrapments become more and more elaborate requiring the lady to suffer quite some time at the hands of the maid before her husband comes and take advantage of her.
Now she'd like to de-escalate the game because it's becoming more and more demanding.
But she has to do what the husband wants.
The maid gains subtly power and ascendent in the house. It's obvious that the lady can't tie herself in such a complicate way, with some innuendo the maid let the husband know that she's doing the tying. While everything remains apparently as usual, another woman now is doing the chores and the maid has become something of a mistress of the house.
Maybe she's putting the husband in bondage, too?
Well, what a story. I guess this could be very long, probably too much.