The feeling of euphoric happiness or sexual pleasure that occurs when a Craig Ferguson fan sees him do or hears him say something very sexy. This feeling is most often felt by cougars and teenaged girls. Something that is prone to give someone Fergasm is said to be Fergasmic.
"OMG, Craig's monologue last night was so hot!"
"I know, I almost had a Fergasm."
"But that part at the end where he opens his shirt and has his legs up on the desk always gives me Fergasm."