The production is set in the warmth of the shvitz in Canning Town, otherwise known as the New Docklands Steam Baths, east London's last authentic bath house.
Cassenbaum wants to convey both the tradition and why the shvitz has given him a sense of belonging.
"I used to see Spurs with my dad, a rite of passage for young London Jews, and I also went to Jewish camp, but I just couldn't get into them," he recalls. "I first heard about the schmeis through family members - my grandad and his friends have been going all their lives.
"It sounded like a hilarious place. And when I asked him to take me with him four years ago he was over the moon." Cassenbaum says he immediately felt at home with Papa Alan and his peers.
"You have all these old boys sitting around. Some have known each other since they were kids and they are all naked and washing each other.
"The language is crude, they are ripping shreds out of each other and some topics of conversation are unrepeatable. Stuff like 'how big is your schmeckle?' is just the tip of the iceberg.
"It is the strangest mix of brutish masculinity and tenderness because they are all lovingly washing each other while at the same time effing and blinding."
The graduate of the Young Writers Programme at the Royal Court Theatre sees the shvitz as the last outpost of the Jewish East End. "Everyone has moved out. You can do a tour of Brick Lane and be taken to an Indian restaurant where a synagogue used to be. It's almost like Jewish life there has disappeared." The same can be said of public steam baths, of which there were once well over a dozen across the capital.
For the 12 regulars at Canning Town, it's a trip down memory lane, or as Cassenbaum puts it, "like stepping back in time and having it all in one room, all the voices, all the banter and all the stories. These are people who have schmeissing in their blood."
But it is not a tradition being passed down the generations. "I was the youngest person down there and hardly anyone my age goes. Maybe it's because you've got to get naked and young lads are not as confident.
"The idea that the tradition and identity could end with my Papa Alan and his friends would be tragic. It is the ultimate Jewish East End experience."
For Papa Alan, 75, originally from the East End but now living in Stanmore, the shvitz is almost a mikveh equivalent. "I've been going since I was lad. I even do a bit of davening if I go on a Saturday, but don't tell the rabbi.
"Traditionally, it was how we'd go and get a hot wash but now it is different. Some Jews go to shul; others prefer the shvitz. It's all the same thing really, only you get to talk in the shvitz, so it's better.
"We talk about rubbish, anything we want really, sport, marriage, sex, women.
"We have a right moan and they're not about to hear any of it. It's fantastic and a proper release from all the stressful things that happen in life."
"After the shvitz we go upstairs and get a big spread put on - salt beef, chopped liver and salmon, it is all there.
"Some men play cards, others have a sleep in one of the beds. You just switch off from the world." And the schmeissing? "You get in the steam bath and one of the boys uses a raffia brush to wash you, it's like an exfoliation technique. You need a lot of strength for it but at the end you're relaxed. It's lovely."
The retired businessman says that many former shvitz colleagues are "brown bread [dead] and I can hardly see, which isn't the worst thing in a room full of naked men. But it means I can't go as regularly as I'd like. I hope my Nick carries on the tradition."
Shvitz regular Eddie Bloom, 65, describes it as the ultimate male bonding experience.
"I've been going since I was 10," he says.
"We go in teams and everyone in the team has a job, be it washing down the benches or taking it in turns to do the schmeis.
"We all arrive at 11am and book the hottest room. We might live all over London but for those few hours we're back in the East End."
Cassenbaum says his show will teach newcomers everything they need to know about the shvitz.
"From the rules of the schmeiss" to the Cockney rhyming slang for Yiddish words, "it will be like an A to Z of shvitz etiquette - and Jewish self-discovery".
Listen to Nick Cassenbaum talking about his experience of having a shvitz and schmeiss
'Bubble Schmeisis' is at the Rich Mix, Bethnal Green, on September 5 and at Camden People's Theatre from October 13-15.
For more info see: www.nickcassenbaum.com
