Don’t make jokes about “that time of the month”, “rags” or “PMT”, etc. Joking about such things is just way off and won’t help them to feel reassured. Do commiserate if you actually know how it feels to have a period. If you don’t, then don’t make it up as you just don’t know what it’s like; be sympathetic but not invasive.
Ask them if they’ve had any water recently. If not, fetch them some quickly. Staying hydrated may help to ease their queasiness and some cramps. Offer to buy them some groceries or a ready-made meal. Or, make them a meal. Run errands for them for the day they feel bad. They’ll be happy to do the same for you when you need it. Bring them a hot water bottle for those dreadful cramps. Or, if appropriate, offer to massage their lower back.
If you have any portable stain remover in your bag or desk drawer, give it to them to use. Don’t make fun of stains and don’t broadcast the fact that you’ve seen stains. It’s impolite to make a big deal out of it and pointless too. Everyone has messy problems now and then.
