Very obvious slave contract.
Now, why did she get teleported to him in bed?
1) Slaves are automatically teleported to bed at night to perform "night duties"
2) Slaves and masters can teleport to each other as a side benefit from the contract. She triggered it in her sleep.
3) The bed, as an additional power that cannot be read by the appraisal device, teleports any willing women/virgins to it when they think of you.
I'm going with 3, because that makes the bed seem way cooler. Though, it's probably 2. And probably the result of the ring. Additionally could be 1,2, or 3, but only activates on the one you love (that bed is rather small after all).
My actual first conclusion was that their dungeons were linked, but she probably wouldn't have been able to change if that were the case. Or maybe they were linked, but she didn't leave her room so she didn't notice