Put a towel down. Or don’t, and just make sure you’ve got a change of sheets ready if you ever have guests over. Period blood is sterile — there’s nothing to worry about unless the sight of blood makes you faint.
Oral sex doesn’t have to be off the table, either — the blood comes out of the vagina, not the clitoris. A tampon or cup coupled with lying on your back (letting gravity keep stuff away from the clit) should set you up just fine.
Katya Downey is the author of The Ubyssey’s “Positively Sex” column.