Best definition
to produce yeast
your mom has yeast coming out her twat.

you stupid yeaster, go pound good cuntrotte

yeaster: define #2
many yeast infections
that girl has had many yeasters
yeaster: define #3
The experience of finding the remants of a Monistat egg on one’s penis, after post yeast infection sexual intercourse.
“Yo, Ashley had a raging yeast infection on Thursday night, so she put the egg in, and then when we fucked on Friday morning, it was straight Yeaster.