That just means you are half connected with your waking world. Half asleep, not fully asleep - so you can feel your body and the dream becomes more of a vivid image than a full 3d sensory environment.

This happens to me in the early morning hours when I am not as tired. Perhaps do a WBTB after 4 or 5 hours of sleep and focus on having a lucid dream when you are still very sleepy. This way the dream will not be interrupted by sensations from the waking world.