That is more or less what Erwin expected.

"Flower petals. I'm... ah..." It seems that mentioning the damn things inspired them, and Erwin stops to cough again. It's not as long this time, but more violently, finishing with him retching from deep in his lungs and expelling the petals with a splat onto the wall.

"I'm coughing them up." Erwin straightens and wipes his mouth with a handkerchief. A few stray sakura petals stick to it.