Prompting questions are open questions created to elicit anecdotal experiences from participants and are not yes/no questions. They are designed in such a way as to stimulate and provoke people's memories by creating a meaningful context around across a set of experiences including the extreme boundaries (moments of pleasure and pain).
These questions are open so that the participant chooses which experience, is relevant or interesting to share. In contrast, direct questions create bias as they narrow the field of enquiry to categories that the interviewer hypothesises are of interest. Prompting questions should be meaningful to a range of participants and for that reason, they should be broad and open.
They are usually designed collaboratively with the project core team who test them with a sample group representative of the population. A good prompting question places people in a context they understand which allows them to tell a story about themselves or someone they know.