Wrap them in toilet paper or in a little bag (you can get lavender scented bags on the same isle as tampons and pads) and throw in the bin. You could always switch to menstrual cups then you don't have to worry about disposing of anything, healthier and cleaner than tampons too.
Tampons CANNOT be flushed!
Tampons expand when they absorb fluids, it can block up your toilet and pipes, it also costs water authorities millions trying to fix the problems caused by people flushing
inappropriate things such as tampons.