I have done something so stupid I still can't believe it.
Maybe I had fallen under the influence of the 10-headed demon Ravana.
The vanquishing of Ravana by Lord Rama is the excuse for Dussehra, one of the wildest of all Hindu festivals.
Towering wicker effigies of Ravana and his henchmen - complete with curling moustaches and wicked smiles - are filled with fireworks, ready to be burned in the climax of a re-enactment of Lord Rama's great victory.
Last year my wife and I took our four children to the biggest Dussehra celebration in Delhi, at the Ramlila Maidan, a vast field outside the gates of the old city.
As the sunlight turned a delicious gold, we joined the jostling queues.
But Ravana's malign influence isn't enough to explain what follows. I blame the fairground, too.
There's an Indian concept called jugaad. It means a simple, cheap solution to a complex problem. Basically - it means bodging it. The rides applied jugaad with breathtaking abandon.
It was as my 14 and 15-year-old daughters and I tottered, giggling nervously, from a terrifying, harness-free spin on a juddering big wheel that I noticed the sheet laid out on the dry mud.
Crouched on it was a man offering temporary tattoos.
Now, I have always hated tattoos. I live in fear of my children getting some ugly doodle etched into their perfect skin. That's why I thought it would be so funny to surprise my wife, Bee, with a fake one.
"How about a heart with her name in it for her birthday?" I said.
I promise I hadn't had anything to drink.
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"They wash off, yes?" I asked the tattoo man.
"Yes, yes, yes," he said.
"Yes, yes, yes."
"Not real tattoos?"
"Yes, yes, yes."
I felt the chrome nozzle of his little machine. I couldn't feel a needle.
He showed me a pot of ink. Well, you'd need ink for a temporary tattoo, wouldn't you?
I pointed to a heart on one of the laminated sheets with pictures of his craft, and then at the letters B, E, E.
"Yes, yes, yes," he said and took my arm firmly.
Before I knew it, he was already at work, and here's the thing: it didn't hurt.
Everyone I know who has ever had a tattoo says it hurt.
All I felt was a prickle. That said, it did worry me, but by then the tattoo man had already inked out a rough heart - and I do mean rough - in the middle of my upper arm.
It must have taken all of 30 seconds.
He started on the letters.
First an L. Hold on a second…
Then a smaller heart - an O.
Now I was really worried. I tried to pull my arm away.
"No, no, no," said the tattoo man, pulling back.
With a sharp tug I got my arm free and wiped in desperation at the ink. But beneath my fingers I could feel my skin was slightly raised. The blue-black ink didn't even smudge.
"What have you done?" my wife wanted to know when we found her in the crowd and showed her my arm.
My daughters were doubled up with glee. Who wouldn't laugh when your dad has just got himself a tattoo by mistake?
The first fireworks exploded in the sky. Ravana was about to be put to the torch. I was already rushing for the exit.
"There must be a way to get rid of this thing," I told myself.
There wasn't. And here's some advice you probably don't need - never follow home tattoo removal instructions from the internet.
Flushing it with gin - the only alcohol to hand - didn't make any difference.
Salification - literally rubbing salt in the wound - didn't work either.
I now have a white scar as well as a cheap tattoo.
My wife was more worried about the risk of blood-borne infection, which is how I came to be sitting in front of a doctor in one of Delhi's hospitals.
So how risky is a street tattoo like this, I wanted to know?
"Oh, infection is very, very, very common," he told me with a huge smile.
He said as well as hepatitis B and C, there was also the risk of HIV.
"Really?" I asked.
"Oh, this is a very, very, very common way to get HIV. I see it all the time. All the time," he said, apparently delighted.
Two weeks later, the results of the blood test came through. It was clear. I have booked another test to make sure that is still the case.
The tattoo, however, isn't going anywhere. Ugly as it is, I'm keeping it - a permanent reminder to be less impetuous.