you should never brush after you've just vomited this is because the contents of the stomach are extremely acidic and the mouth is in a very sick state too if you brush straight after you're basically wearing away your enamel

you should never brush straight after breakfast this is because when you've just eaten the mouth is in a very acidic state so if you brush your teeth you're rubbing that acid on the tooth which is a mineral and can wear it down

to brush your teeth after you just had sweet wait at least sixty minutes this is because when you've just eaten sweets the mouth is digesting it into an asset and that asset is gonna get robbed on the teeth and destroy the enamel so wait at least sixty minutes before you brush your teeth