My hangover ethos was basically that you’ve poisoned yourself and you want to expel the toxins as quickly as possible while putting minimal additional strain on the system. So obviously some type of hydration is in order but I’d eschew a pint of cold water (which will hit your stomach like a tonne of bricks) in favour of some milky coffee or tea, taken slowly, along with some lightly toasted bread and a little butter. Then have a shower, then a wank, then a little more tea and toast. Then another wank, a paracetamol, and get right back on it.