1) When something extra/ unexpected (usually illicit) is added to a seemingly normal item
2) Can also be used as code for asking someone if an illicit substance is added to a non-illicit substance
3) Phrase for an ordinary activity that was unexpectedly extraordinary
Man, that hookah messed me up last night. Was it con queso?
(asking if weed was added to the hookah tobacco)
Are these girls drinks con queso?
(asking if there is any GHB in the girls drinks)
Was that blow job con queso?
(asking if she swallowed)
Dude, that sex last night with the girl I met was con queso!
(meaning you got anal, the sex was better than expected, etc)