A preference for something non-standard to be involved in sex. Common ones include:
NVSP's are a lot less creepy than fetishes to the general public. Basically, the difference between an NVSP and a fetish is that with a fetish, the object/situation must be present for the sex to be enjoyable.
NVSP's are typically just as difficult to bring up in conversation as fetishes, though they are a lot easier to introduce as a matter of experimentation.