Has to be little Johnny!

[rebbonk]

An eight-year-old boy swaggered into a pub, sat on a barstool and said, "I'll have a large brandy and one of your finest cigars, please."

The barmaid swiftly assessed his tender years and replied, "Do you want to get me in trouble?"

Spoiler:

"Maybe later; for now I'll just have the brandy and the cigar."