For those who don't know, Chinese water torture is a form of torture wherein the victim was tied down and water was slowly, incessantly dripped onto their forehead until they went insane.
That is what living with small children is like.
The first night, you sleep a bit less than you'd like, your rest is broken. You don't really care, because you've a tiny human to gaze at and it's all rather lovely. Then you've done it for a week and you've kind of got used to it and you can nap at lunch time, after you've fed the tiny human, and be snuggled up in bed together and it's actually rather lovely. Then after a few months the night waking is less regular and you're getting good long stretches of sleep - hours in a row, consecutive ones, like a real person - and you're feeling pretty damned good. There's a few blips, with teething or growth spurts or nightmares, but generally you're doing ok (except your small person thinks 5am is actual morning, not turning the pillow over and flopping back down morning) and some days you don't even need a coffee to get going.
Then you're pregnant again, and wake yourself up needing the loo or struggling to find a position the person in your abdomen agrees with and the toddler person still wakes you just before dawn, but you're still just about managing because you can still sneak in a nap together, since it's just the two of you, cuddled up in bed watching clips from Disney's Cars on youtube on the laptop, or reading dozens of story books together which is actually rather lovely. Gradually though you're getting more tired, and can keep your temper just that little bit less long.
Then you get another tiny new baby, all miniature and squishy, and oh how lovely - except that they wake a lot in the night - and often that wakes the toddler, who wants to come into your bed, so once you've fed and changed and settled tiny person small person is snoring beside you taking up your pillow space and you haven't the energy to carry him back to his own bed, though you're well aware of that whole "Rod for your own back" thing people speak of (but he stays in his own bed until 5 and you figure getting into bed with you at that point is better than insisting you all go downstairs and watch ceebeebies or play trains or do jigsaws and if you hold your breath he might, *might* sleep again for half an hour and you can get that magical 30 minutes that makes the difference between Mummy and Zombie...)
So you're getting less sleep than ever, but you can't nap because either the biggun falls asleep just as the littlun is screaching for milk and by the time he's sorted biggun is awake again and you've missed your chance - OR biggun refuses to sleep at all, but is red faced and furious at every decision or suggestion you make because he's so tired and just too stubborn to lie down.
One night of this and you think the coffee will get you through. Three nights of this you need to add sugar, and have a second cup. Three weeks of this and you're actually losing your mind and forgetting things, like how to unlock the door, where the lightswitches are and your own name. Then, for added joy, the baby decides that 2am is plenty late enough for you, you slugabed, and insists for a few hours that you get up - then it's 5am and the toddler has joined in, so you give in and come downstairs and make the coffee and are just managing to convince your eyes that they need to be in open mode when the baby falls asleep, and snores, smugly, on your knee. Then the toddler dozes off - and you think "Oh, oh, oh - I can go back to bed!" - then close your eyes, just as the baby starts to snuffle around for some milk...