16/09/2016 3:39 PM AEST | Updated 19/09/2016 11:42 AM AEST

The Weirdest Sex You Will Ever See That's Totally Safe For Work

The birds, the bees and penis fencing.

Bob Halstead
Flatworms attempt to impregnate one another. This is not made up.

Your high school sex education class probably didn't cover penis-spearing flat worms.

Or oceanic sperm casting. Or the private world of pollination that involves a third partner from (gasp) another kingdom entirely.

Lucky an Australian has co-edited a special edition of journal Nature titled 'Weird sex: the underappreciated diversity of sexual reproduction'.

To get you in the, ah, mood, here's a video of flat worms doin' it. The only challenge is, they're hermaphrodites with both male and female parts, and they're simultaneously trying to impregnate the other while not being impregnated themselves.

It's called penis fencing. And no, none of this is made up.

University of Sydney professor Madeleine Beekman told The Huffington Post Australia the project was an education.

"I now know a lot about sex," Beekman told HuffPost Australia.

"The genesis for the project was while having lunch at a conference in Copenhagen.

"We started to talk about things we didn't quite understand, and for some reason that topic then turned to sex."

She said a gap in knowledge was an opportunity to discover something new.

"I really didn't know very much about plant sex so that was the paper I co-wrote for the edition," Beekman said.

Ron Oldfield
Up close and personal as moss gets jiggy.

"I had questions about pollination; about how plants chose the right sex partner when pollen goes where the wind takes it.

"Is there a chemical communication between pollen and the plant to make sure it's letting the right one in?"

She said she had a newfound respect for sex among bacteria and algae.

"We're all animals and we think what we are is the standard, and other organisms have 'weird' sex, but when you think about it, we are the minority compared to bacteria and other organisms.

"Bacteria can just basically swap genes, it's how they can so efficiently mutate to form resistance.

"It's really bizarre."

Greg Pease
Bacteria doesn't need privacy to get it on.

One last piece of advice she has learned from co-editing the special edition is a practical one.

"Please don't look up 'sperm casting' on Google. That may be the next correct name but when you search on Google, things come up that are definitely not sperm casting in the ocean."