You probably know Caitlin Moran as a fearsome tweeter, award-winning newspaper columnist and the author of 2011's hilarious feminist manifesto How to Be a Woman. But with her sister Caroline, she's also the co-creator and co-writer of Raised By Wolves, a warm and witty Channel 4 sitcom based loosely on their unconventional home-schooled upbringing in the Midlands. Set in the present day, it follows formidable Della Garry (Rebekah Staton) as she raises five daughters named after feminist icons (and one son named after a Kevin Costner character) in a crowded three-bedroom council house in Wolverhampton. With series two about to begin, we met up with Caitlin and Caroline to find out what writing a TV show with your sister is like.

How would you sell Raised By Wolves to people who didn't watch the first series?

Caitlin: It's a show about the kind of girls you don't normally see on TV. Della is a single mum who gives no shits. There are a million books about motherhood and you're supposed to study them like fucking art. Della knows nothing about that. She's treating being a mum like being a superhero. She's basically Linda Hamilton in Terminator, but with five daughters who are all girls you haven't seen on TV before. Aretha is a depressed ginger intellectual, Yoko is kind of psychic and Germaine is a walking vagina who says all the wrong things. And they're living in Wolverhampton. Did you see that poll in the paper? Wolverhampton is the most unhappy town in Britain, but it's also the least anxious. So the mentality is like, 'Yeah, we're unhappy, but we don't care!'

The first series dealt with topics like masturbation and menstruation. Where do you go from there?

Caitlin: We're exploring their world a bit more. We get to see Della's job. I think in the first series everyone presumed Della was on benefits, but no, she has a demeaning minimum wage job that she's very angry about.

Caroline: And the kids go out into the world more because they're that bit older now. Germaine has discovered she can get love action, so now she's out harvesting love.

Caitlin: Yes, there's a lot of love harvesting going on! Germaine comes up with an idea in episode one that's so disgusting, everyone presumed I had written it. But it was actually Caz. You don't normally go there with the bodily parts stuff, do you? People asked us how we were going to top plots about first periods and first wanks, but I think with this series we have.

Are there any particular challenges to writing with your sister?

Caitlin: The challenge is stopping yourself from talking about family gossip. We can waste an hour talking about whether our sister suited the scarf she wore last time we saw her – or whether we should do an intervention and tell her pastels aren't really working for her.

Caroline: But it's mainly useful because the characters we're writing are based loosely on ourselves [Germaine is based on Caitlin, Aretha on Caroline]. We just have to make sure it doesn't tip over into, 'And then Germaine does something really vindictive...'

Caitlin: Or 'Aretha had nothing funny to say for well over nine minutes...'

Caroline: Or 'And then Germaine did a poo with the door open'.

Caitlin: I'm re-pitching that idea for series three! I think an entire episode where Della's out at work and Germaine's stuck on the toilet with cystitis trying to rule the house remotely could definitely work.

Caroline: But we spent a lot of time together as kids because obviously we didn't go to school. We were basically stuck in a room playing with Sindy dolls and that's a lot like scriptwriting. Jill Soloway, the woman who created Transparent, was asked recently, 'What are the challenges of being a female director?' And she said there aren't any because we're brought up playing games with dolls and that's a lot like directing. And I thought, 'Yeah man, that's the same as Caitlin and me playing games with our Sindy dolls and now writing these scripts together.

How did your family react to the first series?

Caroline: I think they'd almost been expecting us to make a show based around their lives. Some people were a bit outraged because there are actually eight children in our family, whereas there's only six in the show, so we had to merge some people into one character. Some people weren't represented and umbrage was taken over that.

Caitlin: That was an awkward Christmas dinner conversation, where someone would ask, 'Which character am I?' and we'd have to say, 'You're part of a merged character.' They'd be like, 'I'm a merger? Am I not enough of a personality to be in it on my own? Thanks.' People didn't want to be merged. I think they confused it with being shipped.

When Raised By Wolves is on, do you check Twitter to see what people are saying?

Caitlin: My husband will look and tell me what people are saying, but I can't because it's just too embarrassing.

Caroline: I don't really go on Twitter anyway, but if you want to have some bad mental experiences, go and look at the hashtag for any television programme that's on and you'll be shocked.

Caitlin: That's the nature of Twitter. People don't generally go on Twitter to talk about something they like. If something's good, you're absorbed in it. Maybe you'll tweet about it at the end of the programme. There are whole departments at TV companies monitoring Twitter misunderstanding the fact that people generally go on Twitter to be bitter.

Caroline: And that's an enjoyable thing to do. If people wanna have those conversations about Raised By Wolves, it's cool, but the last people who need to be looking are me and Caitlin.

Caitlin: It's like modern art. It's not so much what you've created, it's the space between the art and the person who's viewing the art: What are they saying about it? That's what Twitter is. So if someone wants to hashtag #CaitlinMoransFatFace, that's a valid piece of modern art, though I do wish my mother would stop doing it now.

Series two of Raised By Wolves begins on Channel 4 in March.