An improved teat cup, teat cup sleeve, milking machine and milking method provides cleaner milk by drawing air into the milk stream from away from the teat cup. The teat cup may include an air duct having a first end in fluid communication with the milk conduit extending outside of the shell to a second end located away from the shell of the teat cup. The air duct may form part of an air passage that extends between the milk conduit and an air inlet which allows control of the source, flow and purity of air entering the milk stream.