A Monte Cristo is a slang term for having sex during a lunch break. Used interchangeably with nooner. Its usefullness comes from the fact that a Monte Cristo is also a popular sandwich, so a the term can be used to disguise one's actions around unknowing co-workers.
'How was your Monte Cristo, Nigel?'
Denotes a sex act whereby one coats thier cock in raspberry jam and ass fucks another person.
This freaky ho couldnt get enough so I gave her the monte christo so she would shut the hell up and I could get some sleep.