The hocker is a sexual position whereas a female (or male if you are into that sort of thing) is laying on her/his back on a bed or other raised platform, with their head falling off the edge, and you, standing insert your penis into their open mouth at the same time cutting off their air stream by letting your ball sac cover their nostrils–as you proceed with a rhythmic pumping motion-which leads to a sound resembling a "hock-hock"
Man - Do you know Hocker?
Woman - No, who is he?
Man - Lay down on the bed and drop that pretty little head and I'll introduce you
Woman - "hock, hock, hock"