You have to clean your tongue. Get another toothbrush and keep it just for your tongue and somewhat sterilize it after every time you use it by soaking the bristles with mouth wash and let it dry with the mouthwash. Cleaning your tongue with a little toothpaste or something with remove the yellow fuzz that coats the entire tongue and is disgusting and smells. Also over a short time things like a lot of pasta for an example or maybe too much bread or maybe anything can build up hardened yellow rocks that become lodged inside the small pockets that line the inside of the top of your throat. So look in a mirror and with your finger(s) press on some of the areas inside the back of your throat and some of these yellow mucus balls may drop out of the pockets of the skin. Yes this may prompt your body to want to gag a bit but be gentle and it will be fine. Also do not swallow these things. These small yellow rocks smell horrendous and is one of the leading causes for bad breath along with a stank tongue.