I'll raise the Chinese flag in a minute!
She's naturally horney during her cycle, that's a good thing! Hell, take a shower together, do the normal hygenic things that women normally do, go for it like it's your last time!! If you worry aout the sheets, put a dark colored towel down, it's a done deal for me.
FYI, soapy water washes off the blood right off if there is any, it's not some toxic radioactive waste.