To pull a curt, is to say the most inappropriate thing yoo possibly could, to a female and make her question your friendship... unintentually.
girl: omg! yoo so look like the type of guy to have had a fair amount of girlfriends!
guy: are you calling me pimp..?! do you see me as some kind of man-whore?!
girl: what..? no!
guy: you know what... just go!
(the guy will keep this up, thinking its purely a joke...
but unintentually hurting the girls feelings. i.e pulling a curt)