Super quick:

Can anyone give me the names of any chapters of all the HP books in which Voldemort is using Occlumency? I need to describe the feeling both the invader and victim might feel, so any good Occlumency-being-used passages will do.

Also, can anyone give a name to what the invader is called while taking information from the victim's mind? More simply, what could the invader's mind be called? Just 'his mind' or 'his presence' in the victim's mind? Both 'mind' and 'presence' don't completely make sense to me, and so I've decided to seek some more brainpower.

Do reply.