Subtweeting has become such an ingrained part of online culture that you don’t even need Twitter to do it. Just throw a vague, personal jab on Facebook, Tumblr or Snapchat: Ta-da! You — such as luminaries Khloe Kardashian, Mitt Romney, Texas Supreme Court Justice Don Willett and the Redskins — have just successfully subtweeted™.

But just because it’s so easy to subtweet doesn’t mean you should. In fact, you should pretty much never subtweet unless you really, truly don’t care about what people think of you.

This it at least my personal takeaway from a forthcoming study on subtweeting, conducted by researchers at Western Michigan University and slated for the journal Computers in Human Behavior. (Yes, we live in a brave new world where even the most petty habits of Twitter users are subject to research.)

Essentially, Autumn Edwards, a professor of communications, and Christina Harris, her grad student, recruited 349 undergrads and asked them to rate four tweets on a series of reputational measures. Two of the tweets were nice; two were nasty. Two were “direct,” naming their subject, and two were subtweets.

What they found, when they analyzed these responses, is that readers formed consistently bad impressions of people who subtweet: They’re less likely to want to befriend them, less likely to think they’re socially competent and less likely to think they shared any personal similarities. They also found that, by and large, those negative impressions spring from two separate things.

First off: People do not think highly of people who tweet nasty things. It’s the same principle that applies to real-life mean girls: They may seem like the cool ones, but they’re hated secretly.

Two: People take it as a sign of rudeness, even ineptitude, when others are deliberately indirect or vague in conversation. Because that’s exactly what subtweets are designed to do, you may want to avoid them unless you’re trying to make a bad impression.

There is one exception to the #neversubtweet rule, Edwards said, and that’s if you feel utterly compelled to tweet something mean: In which case, people will already think you’re a jerk, but less of a jerk than if you called out your victim personally.

TL;DR: Your mother was right when she said you should keep your mouth shut if you have nothing nice to say.

Unless you’re being ironic, of course. The ironic subtweets can stay.