That's when it all went wrong. All puffed up because, for once, the little blighter seemed to be listening, you fell into the trap and came out with the fatal words ... "If you practise hard, you will soon learn how to operate it."
I suppose people have said things that were even more disastrous. After all, the order which started the charge of the Light Brigade wasn't a roaring success - and whoever it was who suggested pulling the wooden horse into Troy didn't do too well either.
Still, on a domestic level, telling a young boy to practise indoors with his helicopter ranks quite high.
The result was immediate. There were screams from his little sister as the helicopter chased her around the house; howls from the dog as the rotor blade clipped its ear; shouts of outrage as the vase containing grandmother's ashes was knocked off the shelf and shattered; and, for you, the author of all this chaos, there was the task of replying to an excited questioner: "Do you think I'm better at it now?"
Now, no one wants to discourage the young from practising anything, so it wouldn't do at all to countermand the previous advice. Something more subtle is called for ... some sort of accident which wipes out the helicopter without doing psychological damage to the child.
Ah, yes, just the thing - there is a large wasp in the kitchen. The accomplished athlete can account for it with a single swing of the tennis racket. Oops - you got the helicopter! It seems to be dead and the words addressed to the sobbing child are designed both to praise and to bury it.
None of this matters very much - households always have their share of disasters. The trouble is that it's going to get a lot worse - and the reason for that is drones.
Drones have had a good press generally and they promise to be very useful. Flying above the traffic, they will be able to deliver things safely and easily. Need some more olive oil? The supermarket drone will be with you in minutes. Slip over in the street? A drone with sticking plaster and disinfectant will soon be at your side.
What's not to like about drones - unless, of course, you happen to be an enemy of the West?
The answer is in an article last week which suggests those addicted to the selfie will want to be followed around by camera-carrying drones so that their every act is recorded on film for posterity.
Now that sort of thing has long been usual in the bedroom where perverts, blackmailers and secret agents are expert in the technology of one-way mirrors and hidden lenses. But everywhere and openly?
Imagine junior football matches with little Johnny being followed up and down the field by the parental drone, its camera following his every movement. With two full teams there could be 22 drones in attendance.
Suppose it is rugby and there is a scrum - will the drones hover above, blocking out the sky with their wings until they crash into each other and fall on the players?
It won't just be sport that is ruined - drones will replace the paparazzi, flying low over the south of France looking for movie stars sunbathing topless. Worse still they may learn to communicate with each other so that the call will go out in dronespeak: "Miss Lovely lying next to someone who is not her husband" - at which the air will darken with the beating of wings.
Obviously such intrusions on privacy will see people buying jammer devices to interfere with the drone's control mechanism, so you press a button from your sunlounger and watch them crash and burn like space invaders.
Sadly, it'll probably never get that far - some sort of drone licensing scheme will have to be introduced so that only good people such as supermarkets, the military and bishops of the Established Church will be allowed to operate drones.
The rest of us will either be left droneless or will have to mount pirate operations. Actually the latter could be quite fun - particularly if you happen to be an 8-year-old boy.
John Watson is the editor of the UK weekly online magazine The Shaw Sheet, where he writes as "Chin Chin"
