Lore/context:

Black Record is a very heavy weed user of many years (canon), but Strawberry Cocoa just loves femboys cuz [s]he sees them as a very special group (canon), and he has the time (and money, not to mention patience, since femboys practically make SC into a perpetual motion machine) to rehab a weed-using one.

After meeting this a little older stallion and his friend-with-benefits, whose relationship he found out to be damn close to being depressively bad (canon) by the standards (of The Coco Clan, and with Princess Luna or Prince Artemis) he's accustomed to, he's determined to help them, so getting him to drop the drug is only 1 way.

Burning up a cigarette is a bit extreme since quitting the weed ain't as simple as just not doing it, especially after such a heavy usage for so many years, but the point is sending a message. SC can get him a new one with his own money, or roll one up, as an apology.

Note: SC is supposed to be saying "I'll help you kick the weed" while kissing and burning up the cigarette, I think the artist forgot or couldn't figure out a way to fit it.