Barmaids are advised that when pulling pints (Real Ales using old fashioned beer engines with manual pumps rather than the more modern fizzy stuff which is expelled from its containers using gas) they should alternate the hand which holds the glass and thus also the "pulling arm" as the constant exercise of one arm in the pulling will result in the development of unwanted muscle in the arm and chest. Since all women have one breast larger (or smaller depending on your preference) than the other, such over development of the muscles can result in an exaggeration of the condition known in the trade as Barmaids Tit.
The symbols used by Barman clearly show this ~ a fact picked up by our very own horny handed son of the soil.