‘You have to let us see you post-coital,’ orders Dr Brown, gently but firmly. ‘When you’re lying there with your lover, dude, and you’re just staring into her eyes, because you just came, you know? You’ve given her everything. You’re not hiding anything, she sees you at your most beautiful, completely vulnerable, totally open. People will be generous towards you. You’ve taken a risk to let them see you in a very special, intimate moment. And they say, “thank you. That’s why I come to the theatre. To see humanity.”’

It’s easy enough to imagine conversations like this happen all the time in Soho. But it’s still startling to witness a man mime his conception of theatre quite so gynaecologically. And with so much emphasis on conception. Dr Brown is not a qualified medical professional. Increasingly, his shows are characterised by a refusal to talk. And he doesn’t like the term ‘alter ego’. But Brown is ‘the pure essence’ of Phil Burgers, maintains his collaborator, the Australian storyteller Stuart Bowden, as the three of us chat outside a London cafe. The hirsute American is a sexualised clown, or ‘bouffon’, who approaches the stage, and making love, with exactly the same playfulness, freedom and desire for others to get involved.

‘If the audience is laughing, why would I pull my hand away?’ Burgers implores. ‘Why don’t I put the finger in? They’re still laughing. Three fingers? A whole hand? Two fucking hands! My head? Why stop, why hold back? You need to cross the wrong line to know where the line is. You have to be sensitive, because every lover, every audience, is different. You start with a little bit of rubbing but eventually you learn how to get them to open up so you can stick your whole body inside. It’s subtle.’

And often, quite graphic. After four years of competing incomprehension and acclaim at the Fringe, like most highly-sexed Californians, Dr Brown has established a cult. He teaches clown workshops and has completed his Comedy Blaps, a series of short, online films for Channel 4 showcasing his origami skills, full-frontal nudity and ‘the same spirit of silliness and stupidity. But I play characters. And I talk.’

He’s returning to Edinburgh with Befrdfgth, which scooped the prestigious Barry Award at the Melbourne Comedy Festival, and the kids show Dr Brown Brown Brown Brown Brown and His Singing Tiger, which won Director’s Choice there, featuring accompaniment from Bowden as the ukulele-strumming feline. ‘Because what Phil does is so spontaneous, I have to be spontaneous too,’ explains Bowden, whose tiger costume was randomly gifted to him just before his first appearance. ‘Musically, that’s similar to jazz. That’s not my style though. I’m not some jazz cat.’

When Burgers realised he could perform an entire kids show without speaking, by incrementally increasing the stretches of silence, it was an epiphany that had more to do with embracing risk than perfectly-timed eyebrow-raises. ‘When a comedian’s not saying anything, he’s saying more. You’re looking at his face, you’re reading into it and seeing all this shit happening. It’s fascinating. And then he opens his mouth and the fascination steals away a little bit. Because he’s hiding behind a word.’

The pair credit performing for kids with boosting their spontaneity and helping them ‘embrace our potential for failure’. Burgers launched his last kids show without any pre-existing material and Bowden only came on board belatedly. But they quickly improvised something entertaining and anticipate ‘totally messing about’ with their recent, award-winning effort.

Equally, ‘I felt what I was doing in my adult shows was so stupid it was essentially a kids show anyway,’ Burgers suggests. ‘Even the content is similar, minus the sexual references and aggression. I’ve taken bits from my last two adult shows and bits I’ve done from comedy nights. With the adult show, there’s a bit of a cool game. You’re trying to win them over, but with kids, you’re trying to give it away.’

Burgers found that he needed to build a solid wall around himself on stage to protect himself from rowdier adult audiences. ‘It was much more, “I’m going to fuck you before you fuck me”. Kids play the same game but differently. You still have to be an authority figure. We learned that by repeatedly failing, having kids yelling, coming on stage. We learned to move quicker. Now I’m getting some kind of recognition, I don’t want to fight anymore; it drains my energy and soul. I just want to play, to feed off the spirit of their imagination and lose the cynicism that used to be in my shows.’

Brown’s clown doctrine has its origins in Burgers’ education at Ecole Philippe Gaulier in Paris, where Sacha Baron Cohen and Emma Thompson are alumni. Gaulier defines the ‘bouffon’ as an anti-clown, existing somewhere between grotesqueness and charm, though for his part, Burgers remembers his teacher ‘beating me up psychologically’ for 18 months. ‘He would say I’m nothing, I’m neither a clown nor a bouffon,’ he laughs. ‘Maybe if he saw me now he’d say something different.’

Preferring the gut, emotional laugh to the intellectual, Burgers writes nothing and develops each routine live, learning how far he can push audiences’ boundaries. He still suffers from performance anxiety – ‘scared shitless’ – but he knows that crowds appreciate the vulnerability and respond in kind, permitting him to take the most outrageous liberties with their personal space and erogenous propriety.

He likens this to playing musical instruments, pings an imaginary umbilical cord between us and, at one point, begins commentating on my every expression and gesture, instigating a bizarre dialogue that’s nevertheless strangely compelling. ‘I want to break down barriers, and to play without pretension,’ he declares. ‘I’m not trying to find anything incredible. I just want to play like you used to play with your brother. Or your friends. Or your love.’

Dr Brown: Befrdfgth, Underbelly, Cowgate, 0844 545 8252, 4–26 Aug (not 13, 20), 9.05pm, £10.50–£11.50 (£9.50–£10.50). Previews 2 & 3 Aug, £6; Dr Brown Brown Brown Brown Brown and His Singing Tiger, Assembly George Square, 0131 623 3030, 4–26 Aug (not 13, 20), 12.45pm, £8 (£7). Previews 2 & 3 Aug, £6 (£4).