http://fdiland2k23drdjqmxgmnjmzb47s3ildy5wyh5t4gk2tgjo3yfdffyyd.onion/kemono/thread/2.html
Especially the way simple wiki (the normal one doesn't fit on my phone) so dryly and matter-of-factly describes it sent me rolling the first time I read it.
Honestly, though, if a Pixiu doesn't have a butthole or a peehole because it's "a creature that only takes and never gives", I don't see why they couldn't have a vagina. Especially with how in the manhua they're shown to be able to freely go in and out of each other's gullets, the Bixie impregnation theory weirdly checks out.