My Dad joined the Royal Marines at 17, I think hecouldn't have his rum ration until he was 20, he was given thruppence per day in lieu, so were anyone else who didn't want the daily rum tot.

When he turned 20 the other marines in his mess gave him a sip from their ration, this was called 'Sippers' and there were also 'Gulpers' when you took a gulp instead of a sip - Great traditions in are Royal Navy.