Tis indeed pretty logical. Once you practice and start doing it more it becomes second nature. If it works for you like it has for me then you'll be golden in no time. In regards to asking her to the party what you suggested is fine. You could be a little cheeky and say something like "Hey, im hitting up this party on Saturday (Or whatever day it is), I think you should come as my trophy?" Or you could even flip it and say "Hey, im hitting up this party on Saturday, come along and I could be your trophy?"

At the end of the day dude, you've been talking to her. Gauge how the comfort between the two of you is and if you could get away with cheeky/cocky without coming across as a tard or being offensive...