Kissing the gunner's daughter was to be given a beating or spanking when laid on the barrel of a gun.

Laid on the slippery barrel instinct makes the muscles tense and the blows hurt more and do more damage.

there are various references to Captain's daughters in bed which seem to indicate that it is just that - including catching the pox which as far as I know is not usually got from instruments of punishment - though if anyone knows otherwise ....

Anne