The term trespassing suggests that one is wandering, placing their feet where they do not belong. In practical terms this is quite true. Just visit any farm or wooded community and one will quickly see signs that scream out, no trespassing. It warns the unwanted guest that there will be consequences for violating entrance.
This is equally true in spiritual work. Psychological trespassing points to the state of mind that is always wandering into the past or future, living in imagination or fantasy. This trespassing creates great sorrow, fear and confusion.
As long as one remains present, focused in the moment, trespassing and its terrible emotional consequences will remain absent. Practice breath counting, sensory awareness, meditation. You will slowly shift to the present moment, free of suffering, the warning of trespassing falling into the distance.