How do you write physical affection between friends without it reading as romantic?

I should say upfront: I don't write romance. My last three manuscripts have had exactly zero kisses in them, on principle, mostly because I don't trust myself to write one without it reading like a Terms of Service update. Categorically unromantic. So when a beta reader flagged a hug between my ship's engineer and her best friend the mechanic — a hug I had written as, generously, the emotional equivalent of a firm handshake — with the note "OK WAIT are they finally getting together??", I was, to put it mildly, surprised. They were not getting together. They had never been getting together. There was no getting-together arc. I built an entire found-family plotline on the premise that these two people are permanently, structurally just friends, and somehow the reader didn't get the memo.

So I did the thing I do at my actual job when a system produces output nobody asked for: I stopped assuming I knew where the bug was, and went and actually read the function.

A hug is not romantic or platonic on its own. It's neutral input. The reading of it depends entirely on what is happening around it. Same action, wildly different output, depending on what you put into it. When I re-read my work with that readers feedback in mind, I went through every physical-contact beat in the manuscript and started tagging them like log lines: whose head is this in, what does this scene dwell on, what happens in the three beats after? The pattern showed up almost immediately, and it was humbling, because the hug itself wasn't the problem. It was what I'd bolted onto either side of it without noticing.

What I discovered is that I'd given my POV character a beat of noticing. I'd described the warmth of the contact and the ship's mechanic registering the height difference. None of that is explicit romantic content. I didn't include a swoon or a pounding heart; nothing you could point to and call a romantic tell. But noticing a friend's body and lingering on the sensation of contact is, structurally, the exact move romance writers use to signal attraction. It doesn't matter that I didn't mean it that way. The reader's pattern-matcher doesn't check your intentions; it checks your syntax.

Once I saw that pattern, I started seeing it everywhere in my writing. Romantic contact almost always gets held a beat too long. It's a hand that doesn't quite let go, or a hug that runs on past the point where either person needed it to. Platonic contact, in the stuff I actually admire (I'm thinking of the crew dynamics in shows like Firefly, or the found-family ensembles in a lot of the space opera I grew up on), is brisk. It does its job, it's over, and nobody comments on it afterward. My engineer's hug ran four sentences past the point of usefulness, which is apparently a marriage proposal in prose terms.

I also hadn't given the touch a job, which sounds obvious written down, but wasn't obvious to me at 11pm rewriting a chapter. If the honest reason a hug is happening is "I wanted a tender moment between them," that instinct is a romance convention, whether or not you're writing romance. Give it a function instead: relief after bad news, the reflexive squeeze when someone gets good news, the shoulder-clap that's just how these two have always said goodbye, hauling someone up off a deck plate because the ship just lurched. A touch with a job reads as a touch with a job. A touch that exists purely so the reader can feel something reads as foreplay.

The history between characters matters too. Their history is their context, and if it reads as something more-than-friends, then readers will make inferences from that context.

Here's what I mean: the history I'd given them was bickering. Barbed one-liners, mutual exasperation, one of them always turning up right when the other one needed rescuing, a running list of small grievances neither of them will drop. In my head, while I was writing, that was a neutral history, but for a reader, that follows a lot of romantic tropes. That's the shape of friends-to-lovers, (or maybe even enemies-to-lovers depending on the severity of the bickering), which shows up in about half the romance-adjacent plots I've ever read. I didn't give my characters a friendship's worth of history; I gave them a slow-burn's worth of history, and then I acted surprised when a hug on top of it read as the payoff to a slow burn. Readers don't just track what's happened between two characters in a single scene, they track context, and there are context clues that readers have been trained on a hundred times to read as romantic setup, independent of whether anyone touches anyone.

So the fix wasn't "give them more history," it was "look at what kind of history you're actually writing." A few things helped once I started paying attention to that. I stopped isolating them as a pair. I put them in scenes with the rest of the crew regularly, so the story wasn't quietly implying these two are each other's whole world. I gave the protectiveness a two-way, low-stakes, and non-exclusive quality (she'd have hauled anyone off that deck plate, and the narration says so). And I let other characters treat their closeness as unremarkable, which does a surprising amount of work; if nobody in-universe reacts to two people being close the way you'd react to a couple, the reader tends to borrow that reaction. None of that touches the hug itself. Fix the trope shape and the hug barely has to work for its living at all.

What I actually did, in the end, was ugly but effective: I cut the noticing beat, cut three of the four lingering sentences, and gave the hug an explicit job (she'd just found out the drive core wasn't going to fail after all. It was a hug of relief, not romance). Read it again and it's just two exhausted friends being relieved together, which is what I wanted the whole time. The wedding, such as it never was, is officially called off.