Dear Fellow Fic Writers:
I will pound this into the ground until you GET IT.
When you want a synonym for being cautious, circumspect, or prudent, then the word you are looking for is “discreet.”
The word “discrete” means something entirely different. It means individually separate and distinct.
I know. The quality of being discreet is referred to as discretion, so I see how you can get confused. However, you are writers on the internet. You have the internet at your disposal. A two second Google search can be immensely helpful if you’re not at all sure which is the proper word to use.
And if not, consider this semi-mnemonic aid: When Kurt and Blaine are doing something that requires them being discreet, it is most times because they are not, in any way shape or form, being discrete.