These are specially made small tubes of cotton wool which have a string at one end. You put these into your vagina and they soak up the blood before it comes out of your body. The string is to pull it out when you need to change it.
Some tampons have applicators which you might find easier to insert into your vagina. This will be explained on the pack when you buy them or you could ask an adult you trust how to use them.
When you buy tampons read the instruction leaflet in the box which explains how to use them correctly. When a tampon is in the right position you shouldn't be able to feel it, so if it hurts, it’s best to remove it and try to insert a new one.
A tampon can never get stuck or lost inside you and the muscles of your vagina hold it in place. It will expand inside you as it fills with blood so it will look bigger when you take it out.
Always change tampons regularly, every 3 – 6 hours and 8 hours is the maximum time to leave a tampon in. Try to alternate tampons with using sanitary pads and use a tampon that matches the blood flow you have, like not using a super absorbency tampon when you have a light period day.