Framing' means to communicate to your scene partner that you notice that they said something potentially absurd within the context of the base reality. When you frame, you highlight or underline what you find to be unusual so that your scene partner cam.
In a scene, when a character does or says something unusual for the circumstances, the scene partner may pick at that, to question it, to treat it as strange, to be skeptical of it.
Sometimes your scene partner doesn’t realize that they have said or done something unusual. This allows both improvisors to agree that on the first unusual thing in the scene.
"Framing means letting your scene partner know that you feel that they have said or done something unusual within the context of the base reality. When you frame, you highlight or underline the unusual so that it stands out to your scene partner."
- – Upright Citizens Brigade Comedy Improvisation Manual