Here we go.
Detail 1; the existence of Spren.
Spren are difficult to explain, but the best way I have found is to call them "the soul of an idea." Every object has an associated spren, every emotion and shared idea. They do not have a physical presence in the world but many can be seen when something attracts them. All spren can be divided into three categories.
First, object spren. They are never seen in the physical world and exist only as the idea of the object. Simple objects like a stick have the barest intelligence where more complicated and older objects like a well traveled ship can display personality. These are not important for this matter however.
Second, emotion and phenomenon spren. These appear under certain conditions which vary from spren to spren. Emotion spren are obviously attracted to people who are experiencing a specific emotion. The stronger the emotion, the more spren are attracted. Sensation based spren such as hunger spren or exhaustion spren function in a similar way. Phenomenon based spren are attracted to things that are happening, like wind spren flying along a breeze or fire spren appearing on a camp fire. Of a similar intelligence level to object spren, and not the ones important for the vore scenario.
Third, concept spren. These are more complicated, intelligent and rare compared to the others. Their intelligence is comparable to that of a human, though they often do not understand some things about being human (such as being confused by the need to eat/sleep, or not understanding the concept of death). Delving too much into their nature ventures into spoiler territory so I will only talk about one specific group; Honor spren. Like the previous group they are drawn to honorable individuals, being able to talk with them and form a bond.
Detail 2; Spren are able to reside in gemstones.
Detail 3; Several creatures in the world as well as one intelligent race (the Parshmen/Parshendi) have a naturally growing gemstone in their body.
Thusly, a Parshendi or other character you want to use the idea for can take one of these living ideas into their body, lending an anchor to the Spren while gaining companionship.
