I've never had any students worth perving over. Then again, they were all way too young for me. Besides, that kind of thing completely turns me off. Teaching and perving don't mix in my book.
BTW, if you know a fair bit of psychology, then you would know that many of the students claiming, or thinking, that a teacher is perving over them has more to do with an imagined or a subconscience ego issue than anything based in reality. Of course, that doesn't negate the fact that there really are some real bastard pervs in some of the classrooms.