My Two Cents ... XXVI

This week, we'll have a look at an idiom I came across in a Youtube video:

"fill yer boots"

What does it mean?

It is used in the sense of "go ahead" or "help yourself".

Where does it come from?

I found two possible origins of this phrase, both of which date some centuries back in English history.

The first possible origin claims that this idiom comes from the English sailors who had a leather cup called a "boot" and who were told to "Fill yer boot!" when things were good and they could go ahead and get another rum ration. This meaning is first mentioned in a book published in 1818.

The other possible origin claims it goes back even further, back into the 17th century. In that time, cavaliers used to drink and, according to the source, just peed into their boots instead of getting up, thus the meaning of "go ahead, just do it".

My two cents:
I definitely like the story about the sailors better, and I tend to believe that one since I found a book quote supporting this origin. However, it might be possible that the phrase was first used during cavalier times and later adapted by sailors.