5. Invest In Cute, But Crucially Breathable, Cotton Underwear The last thing you need when you're on your period is to be hot and bothered, but that doesn't mean you should have to wear frumpy undies either. Invest in a couple of pairs of breathable and chic knickers — like these from Calvin Klein (£20) — for those days when you want to feel cute but need a little help in doing so. Image Source: Getty Calvin Klein £20 from amazon.co.uk Buy Now