This precept is "Honor and Help your Parents". I'm not going to quote anything this time, as you can find all the information about this precept on The Way To Happiness Website. I'd like to say how applying this precept has affected me personally.
When I was growing up (I still kind of am, but whatever), I wasn't always the best daughter, especially when I was a teenager. After a while of being rude, ignoring them, and doing the usual teenage stuff, I decided to actually acknowledge them as parents. I found out the my decision to thank my parents for always being there for me and listening to their trials and tribulations helped my relationship with them a lot. I happen to have wonderful parents, a luxury that not all people have, and when I decided to believe in them and their dreams, I found that they really believed in me and wanted to help me. The this reciprocation was really cool. I really like this particular precept, because not all kids and not all parents are perfect by any means - but help and respect for them can make them better then you or they thought they could be. Try it some time and find out for yourself how much it really works to honor and help your parents.