Similarly obvious, if there is any liberal/conservative split around the table, utterly prohibit any talk of Donald Trump. Who cares if racist old Uncle Dave loves the orange moron, and the rest of the family loathes him; everyone will still hold exactly the same views on the subject on Boxing Day, regardless of any vigorous (exhausting) efforts to convince each other otherwise.
Ditto conversations about Simon Bridges and Jacinda Ardern. Give up while you're all still speaking to each other. Some things are better left unsaid.
Speaking of… If you feel the urge to make a joke about women and emotions, hot flushes, periods, etc… just don't. Refrain. It won't be worth it, for you or for the feminist in your life. You'll look like an idiot with a puerile sense of humour, and she'll either bite her tongue to a bloody pulp or point out that you're an idiot with a puerile sense of humour and risk looking like the shrieking, shrill harpy she's so often accused of being.
Here's a better idea: if you're struggling to keep your boring sexism under wraps for a whole 24 hours, why not turn it into a drinking game? Every time that you feel the desire to make a sexist joke, drink. And who said feminists were no fun?
It's a good idea to start accumulating feminist brownie points as early on in the piece as possible, particularly if you're male. If the women in your family usually spend hours in the kitchen on Christmas Day, offering to help – or at least to wash the dishes – will save you from murderous glares when you declare how the trifle looks like it was just "whipped up in a jiffy" after you've spent the afternoon drinking beer in the sun with the other men of the family. If the Santa in your household is usually female, it might pay to give her a helping hand on Christmas Eve. Unless you want to unwrap a pair of socks and a box of golf tees for the fifth year running.
If you're thinking about buying the feminist in your life a nice set of oven mitts for Christmas, or one of those new pseudo-fashionable and completely bonkers etiquette guides for modern women, step away from the counter. Actually, if you're planning on buying any kitchen appliances or cleaning-related apparatuses, desist. Unless they've been specifically requested. Heading to The Women's Bookshop might be your safest bet. Or at least steer clear of anything related to activities that men in the 1950s might've described as "women's business".
While you're out shopping for the feminist in your life, you might want to pick up a slogan T-shirt to wear for bonus points on Christmas day. Try a shirt emblazoned with "The future is female" or "Feminist AF". It'll look extra festive this feministmas under that apron you'll wear when you help out in the kitchen.
In short, the safest way to survive Christmas with a feminist this year is simply to make an effort to portray even the illusion of equality. Sure, you'll deprive us of the opportunity to have a rant about the unfair division of labour that falls on the shoulders of women every Christmas – and we're known to be somewhat partial to the odd tirade – but after a year of ranting, we're tired. We'd be much happier to pass you a potato peeler and compliment your apron instead.
And of course, if all else fails, there's always wine.
Happy feministmas.