[cag_ii]

From the wikipedia page (https://en.wikipedia.org/wiki/Dr_Pepper#Marketing):

    In the early 1960s, Dr Pepper promoted the idea of
    serving the drink hot with lemon slices in winter. 
    This idea appeared in the film Blast from the Past
    initially set in the early 1960s.

[gegtik]

hot cola with lemon is a thing in Hong Kong

[zhte415]

Hot cola with slices of ginger and lemon is a great pick-me-up when having a cold.