Literally meaning "jewellery" or "treasure", the yiddish word "schmock"/"shmock"/"shmuck" is usually used to refer to a cocksucking faggot or, if used with a possessive, to a mere cock. Other common yiddish slang words for a mantool are "schtick" and "putz". Each of them bears a slightly different connotation.
Aaron:"Berel is such a shmock!"
Yan:"A shmock indeed and a nebbish and a kaffer. He's been seen sucking putz for mos!"
Aaron:"Yeah, I've heared that mayse. He's meshugge!"
Yan:"He certainly is!"
Miryam:"Berel, stop scratching your schmuck! that's disgusting."
Berel:"Be still, woman! I scratch what I want."
Miryam:"Yea. Nor nisht in public, Berel. Nisht in public!"