Sex with the Winter/Summer Knight of there respective courts. Mab says what the Mantle will do to defend itself. Winter Knight is part of the Winter Mantle as extensively talked about in Cold Days. Mantle can't defend against itself, would probably indulge in it.
Disagree. I rather think Slate's hatred of Maeve is that she used sex to entice him, and when he cornered her on "delivery", the Mantle did its thing.
I also suspect that this is the purpose and point of the Lady *needing* a handmaiden. Dollars to doughnuts, Jenny Greenteeth, shapeshifter, "pinch hit" for Maeve when necessary and available. Tradeoff? Having a secret on the Lady.
So sometimes she gives him what he wants, sometimes she gives him a Ramirez, and his hatred of Maeve makes total sense.