"Oh My Chuck"

Used by fans of the show "Supernatural" as an alternative way of saying "Oh My God" since Chuck the prophet is actually God.

Original Male Character
Used in fanfiction when an original character is inserted into an already existing set of characters/fandom. Often shunned due to fear of Gary Stus, hence it is given as a warning.
See also: OFC

oh my communism --> used instead of God as religion is not okay in the communist utopia. Idiy rabotay suka now.

Oh My Cher, instead of Oh My God (OMG). The phrase is popular in the gay community, whom stereotypically are obsessed with the famous singer Cher.

Oh My Carlisle

Referring to the almost godlike compassion and restraint that the character Carlisle Cullen exhibits in the Twilight series by Stephenie Meyer.

Stands for "old man cock"

Sometimes used to disguise actual meaning when the company around you would take offense to you saying "old man cock."

As in, you can't interact with a webcam (ie. on Chatroulette) without some old man cock popping up on the screen once in a while.

Oh My COD
for Call of duty players it is a replacement for OMG