Menstrual cups and period basics

What is TSS (Toxic Shock Syndrome) that is said to be caused by tampons and menstrual cups?
Based on the experiences of people who have had trouble with menstrual cups, how can you use a menstrual cup effectively?
My period overlaps with the sauna, hot springs, swimming pool, beach, or other marine activities! Can I use a menstrual cup for summer leisure activities?
What I learned from an initiative to teach boys' school students about menstruation
The pros and cons of menstrual cups