WHAT IS A MENSTRUAL CUP? A menstrual cup is a type of reusable feminine hygiene product. It’s a small, flexible funnel-shaped cup made of rubber or silicone that you insert into your vagina to collect period fluid. Cups can hold more blood than other methods, leading many women to use them as an eco-friendly alternative to tampons. And depending on your flow, you can wear a cup for up to 12 hours. SIZES. Small: Recommend for those who are up to the age of 25 years old, sexually active, NEVER delivered a child (ren) vaginally or by C-section. Can be used if you have average or heavy flow. Large: Recommend for those who are OVER 30, sexually active, delivered a child(ren) vaginally or by C-section. Can be used if you have average or heavy flow.