I have added the actions. With your code no one gets Enjoy Anal in Cowgirl Anal positions, which was the case already to begin with. With my code both parties can get it. So the solution is somewhere in the middle.
I've switched my attention from categories to tags and it has... kind of worked? I'm now in a situation where there's a clear distinction between performer and receiver, but the trait is always awarded to the wrong party. If I wasn't so bloody obsessive, I'd take another break.
if lastaction.scene.givertags.has('oral') || lastaction.scene.takertags.has('mouth'):
With this, the game picks up positions where either someone uses their mouth or their mouth is used by someone. But the trait never goes to the person whose mouth is in question, but always to the opposite side.
EDIT: Got it! I found the reason why I can't get the person using their mouth to get the new trait. Enjoy Anal, which I copied and edited for my purpose, is under func orgasm() so getting the trait is checked when an orgasm occurs. Since oral actions are tagged as "noorgasm", you never get an orgasm from them and therefore never get the trait. I just need to place the trait somewhere else and/or edit it so you can get it from someone else's orgasm.