A discard by definition is pitching a card when you do not have to follow suit. So roman discards (or odd/even discards) only apply by definition when you are discarding - not following suit. Most people who play roman play that it applies only to the first discard.
UDCA (upside down count and attitude) applies in particualr when you are following suit ie. a low card = positive attitude; and high-low = odd count. Your discarding can also be 'UDA' (i.e. any low spot discard = lead that suit, and high spor discard = dont like that suit).