Welcome to Penn, where students overlap in webs more complicated than that gross hook–up diagram from "Jersey Shore." Forget six degrees of separation. We’re lucky to get three. Locust is the nexus of this spit web. Running into your own ex is bad enough, what with the loaded glances, attempts at causal hellos and resurgences of old feelings. The equation gets far trickier when the ex in question is not your own, but your friend’s.

Society hasn’t quite labeled them yet, but you know what I mean. You recognize these people, the few out of the ten thousand, but do they recognize you? Maybe you met them once as they left your apartment early one morning. Maybe you’ve just seen their Facebook profile one too many times. Or, worse, maybe you only have details about one rather extraordinary part of their anatomy. Try greeting that with a straight face.

Options abound and no one I consulted in the matter had helpful solutions. There’s the simple “hi,” recommended for when you’re standing too close to do anything else. There’s the periphery strategy, when you noticed they sat down in your recitation, but you absorb yourself in intellectual discussion for 50 minutes, only to give a quick nod as you leave. It’s coy—or something. When did you notice them? They’ll never know. Depending on how things ended with your friend and this paramour, you may need to be gruff. Treating someone’s heart like a beer can pounded during pledging is not deserving of a wave and a friendly smile. If the parting was relatively amicable, friendship may be possible, but start with a clean slate. Referencing that one time you three all hung out might warrant a fake phone call from Mom to end the interaction. Don’t even think about getting flirty, per the warnings of every single person to whom I brought this up. Netflix accounts are meant for sharing, people are not.

Even more pressing than the actual interaction is the report you will soon deliver. Compose your text as you walk away (and you should be the one walking away). Take note of the person’s every gesture and sartorial choice. Be vigilant for signs of weight gain, depression, or worse, newfound happiness.  Drop in reports of your encounter causally, “Did I tell you I saw _____ today?” you say as you walk to Chipotle. Prepare to tell the story over and over, usually at least one more time after the friend declares, “Whatever, I’m over it.” We’re only human.