First of all, no one gets the personal space they deserve on a plane. Accept that right off the bat; do not sink into pity for your seatmate if he is 6’7 and convince yourself that he merits the armrest between the two of you. You are on a plane; you are bound now only by Skylaw. The rules of God and man no longer apply. Wring mercy clean from your heart. I promise that he has none in his heart for you.

Do not hope that he will notice your uncomfortable position and cede you your fair share of the armrest. In the history of time, no man has ever silently anticipated the needs of a woman. (BROAD GENERALIZATION) As surely as your father will never notice of his own volition if the dishwasher is full and start unloading the clean silverware without prompting, no male flier will ever say, “Oh, were you using that?” and gently withdraw his meaty pincer. You are your own champion today, sister. It is a feminist victory whenever a woman makes it through a flight without losing the majority of the shared armrest to the man sitting next to her.

It is possible, perhaps, that once or twice in human history two women who are strangers to one another are seated together. Stranger things have happened. But in all my life, whenever I have traveled solo, I have always been seated next to a man, each one dudelier and more prone to sprawling than the last. I offer my poor wisdom that I might save you from the pain I have endured.

Men are forbidden from using this knowledge. Please do not read the following. I will hold you to an honor system.

1. Make up your mind as soon as you board the aircraft that you will not give up. None of this effort will be worth it if you cede an inch. He will claim immediate victory and you will have uncomfortably rubbed triceps with a man whose name you do not know for a quarter of an hour, and for nothing. This is as much a mental contest as it is physical.

2. Board the plane before him. Do not wait idly by as the rest of seating group 2 clusters around the pre-boarding area. Get in there. Jostle some motherfuckers.

3. Fly clean. One bag that fits in the overhead compartment without having to force it in, and one handbag. No long straps, no smaller plastic bags full of purchases and tchotchkes stuffed illegally within. Travel light; you will require swiftness.

4. You must be seated, with both arms prominently and dominantly splayed across the armrests, when your traveling companion stops in front of you and says “Oh, I think I’m in __D.”

5. The next step is crucial: do not get up to let him in. Tilt your knees to the side and hug them to your chest. Make no apologies for this clear flouting of the social contract. If your size or his will not permit such a maneuver, exit your row as quickly as possible and re-seat yourself while he is still getting situated, then re-claim the armrest.

6. Mark the territory with your menstrual blood.

7. At this point, unless your forearm is large enough to cover the entire armrest, he will attempt to place his own arm against yours. You may choose to allow this, but make sure your elbow is always further back than his, in the dominant position.

8. Cede nothing. Reach for your bag with your outside arm. Move your armrest hand at your own peril. If he shifts, shift with him. If he reclines his seat back, slide your elbow further into the crevice between your seats. To abandon your position for even an instant would mean instant loss of hard-fought territory. Play the long game, and play to win. I promise you that he will not let the social discomfort of touching a stranger’s bare arm keep him from trying to wrestle the armrest from you. Abandon your sense of personal space.

9. If you are in an aisle seat, intercept his meal as the flight attendant hands it to you. Eat it in front of him, screaming continuously.

10. Remember the lessons of the Somme: Grind them down wherever you can, sisters. On planes and on subways and wherever humans jostle with one another for territory. That small metal platform is your birthright. Treat it like the Weimar Republic treated Alsace-Lorraine.