The Sleep Short line by Flux is by far the most comfortable and most absorbent underwear made by the English brand.
It is designed for menstruation and various types of leaks: maximum absorbency is guaranteed by absorbent layers located both in the front and the back, providing total coverage.
The last PUL layer makes it completely leak-proof.
Washing instructions: after every use, rinse it with cold water. Then hand wash or use the washing machine up to 40° (no fabric softener, no dryer) and use it again!