Based on the headcanon that Michael never loses chapsticks.
The most commonly lost thing among young humans is the infamous chapstick tube. That was not the case for Michael Evans. In fact, he never lost his tubes of chapstick. Thinking back on it, he could remember exactly when he made it his mission never to lose one.
Michael had two very prevalent problems: his extremely chapped lips and his hidden feelings for the Marsh boy. Stan Marsh had come and gone from his goth group and it had left Michael less than happy with him, yearning after Stan for quite sometime after. He still associated with the Marsh kid, even privately hung out with him.
So that was why one day when Michael was picking on his lips, complaining up a storm about how much they were hurting, Stan forced him to stop and handed him a generic tube of cherry chapstick.
"Stop picking at your damn lips." Stan sighed, with an annoyed scowl on his face. "Put this on. I'm sick of you bitching about your lips." Oddly Michael hadn't gotten upset with Stan for reprimanding him. He applied the cherry flavored lip salve as Stan applied his own, a fleeting thought of' this is what Stan's lips taste like.' distracting him for a moment before he pushed it away. He thanked Stan for the tube and placed it in his front jean pocket with a small smile on his lips.
Michael completely finished off that chapstick four years ago and he still hadn't lost a chapstick since. Sometimes Stan handed him new ones when he figured Michael would be out. For the most part Michael bought or stole his own tubes. Always cherry flavored, always the same generic brand. It was comforting to the goth kid to have it on him, so he'd never lose them. With his chapped lips taken care of now he only had one problem- his hidden love for Stanley Randall Marsh.