To get toothpaste stains out of clothes you first scrape off the excess toothpaste if there is any to get the most of the toothpaste off the clothing.
Then take a cloth and moisten the cloth with some water and blot the stain on the clothes with the moist cloth.
Then mix a few drops of laundry detergent or even some stain remover into some water.
Then dip the cloth in the water and laundry detergent or stain remover and then blot the stain again and it should remove the toothpaste stain.
If not you can try using some hydrogen peroxide on the stain after letting it sit for 5 or 10 minutes then try blotting and scrubbing the stain out.
Then run the clothes through a wash cycle in the washing machine and it should remove the stain completely.