Bouncing ideas means talking about your project to someone. The aim is to listen to yourself talk about your task, so it is not important if your interlocutor is versed in your topic or not. In fact, some writers find that talking about their topic to someone who is a total outsider helps them to clarify issues.
If you are having trouble solving a particular problem, talk about why you are having trouble. Variations on this method include talking to yourself or talking to a tape recorder, which has the advantage of capturing your thoughts exactly. Some people are most productive in generating and developing ideas when they can move around and create kinetic energy.