Chop and screw vocals

Hello my question might sound kind of dumb but i was wondering if there was a better way to chop and screw vocals in songs.
When i chop and screw vocals i normally take what part of the vocal track i want to chop and screw and import it into FL Studio then screw up the vocal sample and use my midi keyboard to chop it up. i then import the instrumental and the vocal track i got the vocal sample from and press play. when the part comes up i then try to get the chopped and screwed vocal sample in the right spot its suppose to be in then i import all of that into protools. i know that there is a better way to do this so i was wondering if anyone had any pointers.

A good example of an artist that does this is lil wayne cause in a lot of his songs he is rapping then the verse at one point will be chopped up and at one point it will be screwed.