As to the regular question. First you have to be able to sence spirits on your own, second as someone else stated, you need to be able to create a barrier around the area AND yourself. You also need to know what you are doing. As per example, I have had friends very active in the persual of spiritual manipulation, mainly of their own spiritual forms. One of them got bored, and claimed a high-level demon(that actually does exist) was making a portal at the place we were residing for the perpose of taking her with him, for she said(but wasn't) she was a spiritual weapon he wished to posses. The truth of the matter was, there was a demon making a portal to get her, but only because she had painted herself with a target, and the demon was probably one of the weakest you can find that had many much weaker followers. As a point, I felt the anger of the demon she was blaming, as he asked if he could show her something. I made myself like a keyhole, he could only do what I allowed him, and nothing more, lest he be swept away and gone from me. He abided the rules, got her attention in the full front of my eyes, still she did not see, so he did a small stretch, closed the portal, thereby vanquishing the demon coming from it, and left my body. All the while I was aware of what he was doing, and made sure he did nothing wrong