Setting: The middle seat on a Southwest plane. My flight from Boston to Baltimore is delayed. We are stuck on the tarmac for an indeterminate amount of time.

To my left and my right are men, seated in the window and aisle seats. These guys are of above-average height, and they're sitting with legs splayed like tongs. Their legs are touching my legs. I am uncomfortable, mainly because I don't enjoy public thigh-to-thigh contact with strangers unless I'm participating in a three-legged race at a pumpkin festival.

This is a well-documented human behavior known as manspreading. Commonly associated with public transportation, manspreading is the practice of sitting in with legs apart, invading the personal space of nearby passengers.

The manspreading scourge is real. Men Taking Up Too Much Space on the Train offers a robust body of evidence. And some city transit departments are even fighting back. The Metropolitan Transportation Authority in New York is running a campaign encouraging men to limit their legs to a single seat. The campaign features a list of "do's" and "no's," including "Dude… Stop the Spread, Please" in the no column with a little picture of a man who appears to be in goddess pose.

When the New York Times covered the MTA campaign, a reader wrote in with a request: Let's issue fines for manspreading. My new hero Murray Gelman opined, "A summons-and fine-enforced 'one fare, one seat' policy would reduce manspreading more quickly and cost-effectively than 'clever' advertising."

No one is going to enact such a fine on airplanes. Nor will any airline launch a public service campaign in the lawless airplane cabin, where the public is left to hash out power abuses and boundary disputes among themselves. Armrests offer little defense against thighs, which can easily slip below the armrest and onto the middle seat. Flight attendants can help—to a point. A complaint could lead to a seat change, but on a full flight you're pretty much stuck.

I'd love to lean over and politely ask my V-shaped seatmate to move his legs, but cooperation is hardly guaranteed. Some men think they're endowed by their creator to manspread. When Gothamist rode the New York City subway and confronted manspreading passengers, one rider said, "We have no choice to have our legs like that. You know what I mean? It's different for a woman."

Guys, maybe you don't always realize it, but sometimes you're giving your man parts more space than my entire body. One ticket, one seat. Let's remember to stop the spread.

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