For a play that frankly and often discusses STIs, including HIV, it is perhaps appropriate that the creative team encourages the audience to be sexually healthy. Thankfully, the ticket for 5 Guys Chillin’ is a condom and a packet of lube. We are in good hands – and so are the characters, who continuously stroke and caress one another.

Within minutes the cast are stripping, mostly into tight shorts but most memorably into a leather piece with a conveniently large hole at the back. B (Michael Matrovski) seems nonchalant towards most things: his bum hanging out in the front row’s faces, sex and – most disturbingly – HIV. Such serious revelations don’t come until later though. Right now, B wants to hang out with his boyfriend R (Elliott Hadley) with whom he has a (very) open relationship, and see who else might catch his eye. The chill-out (or raging orgy, for those in the know) is hosted by funny and at-ease J (Damian Hughes) who has also invited the more serious, quieter M (Tom Holloway) and PJ (Shri Patel), an Asian man who seems newer to the scene. Soon they are dancing, taking drugs and chatting.

Interviewing anonymous gay men, then reframing the 50 hours of audio to fit limited resources, and still managing to truthfully and sensitively reflect the reality described without judgement, is an interesting but tricky task. Though such a project can more easily go spectacularly wrong than spectacularly right, writer-director Peter Darney is a class act, with subtlety, humour and heaps of empathy. It is an expertly delivered tight-rope-level balancing act – from the shockingly amusing to the horribly saddening, and from almost philosophical debates over the details of gay culture to the animalistic, primal and unchecked need for sex.

“To wear or not to wear condoms?” might be fiercely discussed. Moments later, this could give way to kissing. All these changes of tone are seamless: the switch from conversation to sex is dealt with cleverly, by turning up the music, charging up the tension and letting the characters dance, grind and kiss. It is a hypnotic time-hop, representing much more than the audience see: we are only watching five men rub each other, but it certainly feels naughtier than that. And given so much of the conversation is about sex – disgustingly, at times – the fairly minor (well – minor, in context) nudity and sexual simulation we see on stage doesn’t feel like an avoidance, but necessary for other aspects of the play to blossom. Once the music stops, the lights brighten and the characters return to their seats, still touching each other, but chatting.

And then come the laughs: “I relate,” I heard someone mutter behind me after one character bemoaned the effect of drugs on the ability to orgasm. Fisting is later described as “the closest I’ve come to a spiritual experience”. And, don’t ask, but ‘Let It Go’ from Frozen will never be the same to any audience member ever again. Yet, moments later, the script can slip effortlessly into something horribly harrowing or psychologically fascinating. When a few of the characters discuss the tendency to specify “no Asian men” on the gay dating app Grindr and shrug it off as simply a type, PJ hunches defensively in the corner. In the closing scene, R reflects that, ultimately, he prefers the nights of his relationship when they are cuddled over a DVD, just as his boyfriend is straddling another man, oblivious to the comment.

The acting is as mesmerising as the script, and as naturalistic. There is no plot, but there doesn’t need to be. It is a marvel: everywhere you look, a story is being told. While two characters might be talking about the pros and cons of condoms, two more will be gazing at each other in the background and the other dancing. Together, the actors and creative team expertly and convincingly immerse us into the modern, app-dominated gay scene, in a psychologically honest play to which anybody – gay or straight – can relate.

5 Guys Chillin’ is playing at the King’s Head Theatre until 24 October. For more information and tickets, see the King’s Head Theatre website. Photo: Kasia Burke.