My partner’s head was between my legs when I felt a splitting pain at the base of my skull. It was as if someone was trying to crack it open with a teaspoon – as if it was a boiled egg about to spill its yolk. At 24 years old, I had chalked up my fair share of experience, but this was a new sensation at the height of orgasm. Even so, it was 3am and neither the worry nor the pain stopped me from falling asleep.