What does it mean when someone accuses you of being "up one's own backside"?

What does this mean in more plain and simple English? Is it a bad thing and why? Does it have any advantages? What's the opposite? What other styles are there? Which are the best styles and why? If you believe that being up one's own backside is undesirable or highly undesirable then please say why and please explain in detail the principles of much better approaches to life.