Not all men are turned off by a woman on her period. To some, the idea of sex with a woman during “that time of the month” is indeed a turnoff, gross, icky, messy, unthinkable. Others don’t really care one way or the other, women are the same, some wouldn’t consider it, others don’t care either way. Some men however not only do not mind, they have a fetish for it and prefer it to the non menstruating time. There’s ones that have a fetish for peeing, golden showers, even for scat, and I don’t care what way you slice that, it is just nasty anyone is into that, but some do love when a woman is on the rag so to speak.
It certainly could be said a woman is womanly at that time, but that’s a bit too womanly for most. You can have such bad cramps you want to die, so blood or not, when in such pain, anyone touching you is the last thing you want, but if cramps are not an issue, have at it. Some guys that don’t care about fucking a woman during that time might not want to go down on a woman then, that might be a bit too much to ask, but some are very eager to go downtown no matter what else is going on down there.
As long as both parties are good to go, enjoy. At worst you can have a shower together afterwards, not that big of a deal. Put down some towels and make love to your lady like not a thing is different. Make her feel you love her no matter what, that a few teaspoons of blood isn’t going to chase you away. She will thank you for it.