We’ve all felt that flush of shame when someone tags us in a terrible photo on Facebook, or we’ve tweeted something and instantly wished we could take it back. But what if it was far worse than an embarrassing selfie or misjudged comment? Sharing isn’t always caring, as we’re about to discover in Charlotte Josephine’s BLUSH, an intense, exhausting and impassioned two-hander.

Directed by Ed Stambollouian, BLUSH delves into the world of social media, with all its practical, social and psychological side effects. We now live in a world where anything we do at any time can be made public, whether by our choice or not. At the same time that world provides sufficient anonymity for people to behave in a way they almost certainly wouldn’t in real life: make vile comments on a video of a teenager that her boyfriend posted as a joke; make public naked selfies that a young woman sent privately through a dating app (and then use them to blackmail her into sending more); make rape threats against a girl on Twitter because she turned down the advances of a man they don’t even know.

These are some of the stories told by the three women and two men played by Charlotte Josephine and Daniel Foxsmith in BLUSH; at first in an orderly fashion, taking it in turns to step up and tell their story, the show becomes increasingly frantic and chaotic as it builds to a climax, leaving both actors out of breath and dripping with sweat, and the audience feeling we’ve gone through it all with them.

The script is descriptive and at times verging on poetic (opening with a particularly graphic picture involving 30,000 pairs of eyeballs) without ever feeling forced or inauthentic. And the set is literally that – a film set, surrounded by lights and cameras, with a circular red carpet at the centre that could be interpreted in several ways: the “stage” of a TED speaker trying to reach out to an audience; the record button on a camera; the embarrassed blush of the show’s title; or maybe just a big stop sign.

The presence of a male and female voice means we also get to explore the fascinating and distressing gender imbalance at play. A young male professional on a high-profile business trip gets drunk and tweets about a girl who turned him down, unleashing a torrent of hatred – against her. In response he gets a slap on the wrist and is whisked back home on the next flight. Simultaneously, a young woman whose boyfriend has ghosted her posts explicit images and videos of him on the Internet – but the instant backlash is against her, not him.

The play makes no attempt to justify this behaviour on either side, or to suggest answers (though there is a pointed comment at one stage about the ineffectiveness of the law on revenge porn); instead it focuses on making us aware of the dangers lurking and the countless ways both we and those around us can be affected by our widespread need for validation. Importantly, though, BLUSH doesn’t indulge in victim blaming; quite the opposite – it goes out of its way to be clear that the fault lies squarely with those who feel the need to take advantage of others’ vulnerability.

Hard-hitting, complex and hugely topical, at a little over an hour BLUSH feels both mercifully short and not long enough – and certainly makes you think twice about reaching for your phone the moment it’s over.