More than just a snappy title, John Fitzpatrick's play is a smacker in both senses of the word. Raw, uncompromising and very beautiful, it's also hilarious – the kind of skilful play that sneaks in unannounced to the Fringe, leaving vapour trails of brilliance in its wake.

Anthony (Simon Carroll-Jones) is an uptight, somewhat OCD young man in a full-time relationship with Gar (Lewis Hart), who's somewhat feckless, and given to letting his groin take over. When Gar meets free-spirited Albert (James Parris) in a supermarket, sparks fly and the two embark on a sexually-charged affair, characterised by 'truth or dare' .

So far, so clichéd? Not so, as Fitzpatrick's crushing dialogue, astute direction by Kate Sagovsky and unpredictable detours are flawlessly integrated in a piece which is so humane and delicate that it feels like an intrusion at times to watch. A funeral speech in a wedding dress becomes a symbol of defiance, and bursts of domestic violence are unexpected and horribly rendered. But the cycle of damaged relationships just keep repeating, like karaoke songs at a wedding.

Suddenly, a childhood nickname of Sandwich is explained. Anthony turns to comfort eating, as things fall apart: who the filling in the sandwich really is, however, is never made clear.

Zoo, the Pleasance (0131 662 6892) Aug 9-31 (not 16,24) £9 (£7)