[header] How to hide your period from your parents [title] Use toilet paper. [substeps] Wrap a lot of toilet paper around the bottom of your underwear. To play it safe, you can actually tape the toilet paper pad to your underwear with regular scotch tape so it stays in place. 
For added protection, add paper towels, or a kleenex, since they absorb a lot more than the toilet paper. Though, when wet, they aren't very pleasant to sit around with.