There is this sick teacher in my school.?

When in doubt, always report odd behavior. Teachers are--and should be--held to a higher standard. This type of behavior is quite simply unacceptable and dangerous. You need to speak to an administrator as soon as possible. You should also encourage other students to lodge complaints so that it is not simply a case of his word against yours. If the administrators even attempt to brush off your accusations, tell your parents and have them contact the school as well.