Any event that is labeled in the guide as burning the girl will meet that requirement. For Alex if she is giving you blowjobs in the forest, pushing her head down as you cum might do it. Similarly for Lina, while spying on people being to Handsy might burn her.
For the most part, it's an isolated thing - save for taking Carla's (bad) advice, or making Sami jealous, there's not a lot of "piss them off to advance the game" stuff. And like the dev said, the beauty of it is that there's always another loop!
Hmm... Thanks guys. I really was just asking as I was confused. There is an option in the settings to take away all the options that would result in a burn. I wish there was a disclaimer there (unless I missed it) that told me I would miss out on paths if I didn't burn them.
