What is "swag"?

In the opening sequence, the professor asks me if I want my rival to have "swag" or not. He says it will make me dislike him more, but doesn't really elaborate how that will happen. What does turning on "swag" do? Can I change this decision later?

Turning on swag makes your rival use the words "yolo" and "swag". I am not sure of the frequency that he will say these two words though. (I am also not sure why I'm calling "yolo" and "swag" "words"...) That is all it is supposed to do, but you may find that the game errors or crashes at certain points depending on if it is on or off. These bugs are being fixed and they may have all been squashed by now.

I'm not aware of what the latest version is, but in patch 1.0.5, a "yoloswag" toggle was implemented. According to the comments which accompany the patch notes, it causes the game to crash.

CHANGE LIST / GLITCHES FIXED
YOLOSWAG Switch added! You can go to your Options menu to turn Swag On/Off midgame!