No, not the Kama Sutra. I'm too old for all those bendy things. It was Hyperbole and a Half by Allie Brosh, and I'm using the term "book" loosely.
What it really is, is a keen observation of the inside of my brain.
I don't know when she had the occasion to peek inside there, or why she thought it necessary to graphically represent it so accurately, but it is so.
I know this because the secret internal thought processes that I keep to myself (and believe me I keep very little to myself) were written out in perfect detail within its pages.
And they were funny.
Funny, funny, funny, funny, funny, funny, funny.
I was trying to read quietly, because that's what you do when you're reading in bed next to someone who is also reading. You don't want to be making a whole lot of extraneous sound effects unless you're actively trying to annoy them for some light relief before going to sleep.
After a while though, I had to giggle. It was tickling my funnybone, and I could no more keep quiet than I could stop reading.
The bad thing about my giggle though, was that it opened something that is commonly referred to as a "floodgate" and a whole lot of other laughter that had been stored up behind it was suddenly released.
I thought each time that I'd got it under control, and then I would read another page, and another burst would - for want of a better word - burst out of me.
After the laughing came the snorting, then the soundless laughter where you're laughing so hard that your muscles all lock up and no sound can emerge even though you desperately need it to.
After the soundless laughter came the convulsions where I almost dropped the book because my whole body was now trying to expel laughter and the muscle groups that normally deal with that detail were unequal to the task at hand.
Then I got to the end of the story, turned off my book, and closed my eyes.
'What was so funny?'
'You wouldn't understand.'
Is there anything better and worse than experiencing a private joke?