"I got frozen pizza and a sponge!" At the end got me.
I totally think with some scissors and a couple of elastic bands, I could make frozen pizza and a sponge into a fully functioning, temporary sanitary towel. The trick would be to not fully defrost the pizza in the microwave so it's flexible yet doesn't fall apart.
If I cut the pizza in a long strip, elongated at front and back to fit the underwear and then double lined the undercarriage with a layer of sponge and held it in place with a couple of elastic bands. It'd be downhill all the way once the pizza fully defrosted, but it'd give a lady time to get to the chemist with her dignity intact.