Coloured lenses only come in a narrow range of base curves and diameters, thus they will not be a perfect fit for most people's eyes and will keep moving around if they're not tight enough. You should go to an optician and get your eyes' base curves and diameters measured properly, then try other coloured contact lense companies to see if any of them make lenses which are the correct measurements for your eyes. If you find that they just don't feel right or make your eyes bloodshot, don't continue to wear them, as you could damage your eyes. I speak from bitter experience - pay attention to what your eyes are telling you, and accept that it might be the case that coloured contacts don't suit your eyes (though weirdly, I can wear daily normal contacts fine, but even Acuvue 1 Day Coloured lenses make my eyes red!)