The faunus of Remnant have a secret that they rarely tell to humans. Every month, they are overcome with lust and desire, as they have evolved to mate every month, and relieve their pleasure at all costs. In other words, it's a bunch of different scenarios of different Faunus in RWBY having sex with humans and each other.
UPDATE: This work is finished, but please do check out the sequel, 'Desires of the Faunus if you enjoyed. Thanks for the support!
- Part 1 of RWBY: Faunus in Heat