Here is an excerpt from an article in the UK's Metro newspaper. It's one of the BIGGEST papers in the country. So it's gotta be true, right??
There’s absolutely, totally, definitively, nothing wrong with going down on someone when they’re on their period.
There’s nothing gross about it. Nothing dirty. Nothing disgusting.
Having an orgasm can alleviate cramps, reduce pain, and even shorten the length of a period (thanks to the contractions of the uterus, which make the lining and blood come out faster).
It also boosts your mood, reducing any PMS-related moodiness in the process, and makes you feel sexier when you’re often feeling a bit bloated and crap.
Receiving oral when you’re on your period makes the most of all that period time horniness (yes, loads of us are extra turned on around our period time, it’s not just you), and the lingering feelings of ‘is this okay? Is everyone else doing this?’ makes it feel a little taboo.*
*Hopefully one day it won’t be taboo, but for now we can enjoy that bit as a turn-on.