Lick an advert at a tube station

Harriet felt a whisper in her ear as she walked up the stairs at Holland Park tube. Lick it? Lick it?!

She had an armful of poppies, and was leaving a trail of paper flowers behind her as she pounded the steps.

Looking left, looking right, she spotted a coffee advert. The one with a lovely lady in cerise, leaning back, held by a tuxedoed stubbled man. It was as large as a person. A small person. Harriet threw herself in its arms, let its soft paper stroke her forehead. It had hands, that poster. She liked it there. Tongue out, she ran her tongue over the bubbled surface. It tasted of cider.