Being self-conscious, in the negative sense, is related with dwelling or perching on something. You are afraid that you are not secure in your seat, so you grasp onto something as you perch. It is like a bird perching in a tree: the wind might blow the tree, so the bird has to hold on. If the bird falls asleep in the tree, it still perches, still holds on. Like the bird, you develop that extraordinary talent to be able to perch even in your sleep. So this perching process goes on all the time. It is not restricted to conscious action but goes on inadvertently as well.
From The Dawn of Tantra by Herbert V. Guenther and Chögyam Trungpa, page 81.