How do you say you smell like vomit in Japanese?

Very impolite way: "Omae gero kusee"

omae = "you" in impolite manner

gero = vomit

kusee = "kusai or stinky" in impolite manner

Polite way: "Anata chotto/sukoshi gero no nioi ga shimasu"

anata = you

chotto/sukoshi = a little bit (to make the person feel less self-conscious)

gero = vomit (medically you use the Word "ooto" for vomit, but it is more written Word and you don't use it in conversation)

nioi = smell