You can just do $this->Teasers() - as this will fall over to the data model your controller is attached to. The general rule is that you access DB fields like instance properties, and relationships like methods.
What should I do if I needed only a few of the entities before extracting them from the database (e.g. sql: WHERE teasers.colour = 'blue')?
And any hints where I can read about this (code, wiki, documentation)?