"Yes," you told them, "you can have magic and sparkles and fairy dust and monsters that go argh.
" Now it's the day before the party and you have nothing done.
As your young buck twirls and jumps and shouts in excitement in anticipation of the following day's events, you feel guilt setting in.
Why, you ask yourself, didn't you just plan ahead? What do kids these days like? You search your metal archives for knowledge, any kind of knowledge, that will give you some idea, however remote, about what kids like.
Nothing, you've got nothing.
You look at your birthday boy and notice him jumping from the sofa, utterly thrilled by his efforts to reverse the law of gravity.
A light bulb goes off: inflatable bouncers.
That's what kids love.
You search online and see every kind of fantasy made inflatable: turreted palaces, clowns with big hands, slides and theme parks, Disney characters..
There's an inflatable bouncer, you soon realise, for ever single theme that every interested a child in the history of children.
You consider you child and their interests and spend no time at all figuring out which Inflatable bouncer they'll love.
It's almost too easy.
The next day arrives and, as you imagined, the party guests go insane on a mixture of pure excitement and unfettered hyperactivity.
They take running jumps at the Inflatable bouncer, screaming out noises that sound like Native American calls to battle.
Your child strolls over to you from across the lawn, takes a drink from the slush puppy machine (another last minute decision on your part) and asks you to bend down close to them so they can whisper in you ear: "Thank you for the best birthday ever," they say.
After you collect yourself and let the special moment sink in, you express your gratitude.
"Thank you, Inflatable bouncer," you say.