A woman or man is 'shcocked' when they see a man's penis for the first or second time and are shocked or surprised or impressed at the length, girth or greatness of the member.
Onemay be 'shcocked' to the upside or to the downside- at a penises greatness or lameness, however, this word is more typically used in the context of an impressive, rather than disappointing member.
OMG- I saw his dick last night for the first time and was completely SHCOCKED! It was bigger and better than I could have ever possibly imagined!