What did the master mean by: “Then thou shalt drink!”?

In The Proverbs, Epigrams, and Miscellanies of John Heywood (1562) among the many historical English proverbs which I recognized, one particular epigram stood out. Entitled “Of Catching a Fly” It isn't particularly difficult to grasp its meaning but a few expressions and one phrase had me puzzled. Here is my translation in modern English

A boy on his book clapped hand to catch a fly.

A boy while studying his book, clapped his hands to catch a fly. (OR)
While studying his book, a boy slapped his hand down to catch/kill a fly

“ Hast her? ” cried his master.

Do you have it? His schoolteacher cried.

“ Nay, God wot I.”

No, God knows if I have.

“ Then thou shalt drink! ”
“ Master, I have her, I think.”

Then you shall drink!
Master, I think I have her.

“ If thou have her,” said the master, “ thou shalt drink ”
To furious masters, what helpeth fair speeches?

“If you have her,” said the master, “you shall drink”
To furious masters, what good comes from *graceful speeches? (eloquent?)

Flies caught, or not caught, up go boys' breeches !”

Whether flies have been caught or not, boys' buttocks go up !

Rare expressions and meanings

wot: the third person singular, simple present form of wit: knowledge, be aware of

breeches: I searched online for the meaning (I already knew they were a type of old fashioned trousers for boys and men) because the phrase “up goes boys' breeches” made little sense to me. I found to my surprise that the singular, breech, is a rare term for buttocks or backside.

The rest seems pretty clear, but what does the phrase, “thou shalt drink” refer to? I assume it's unpleasant because the pupil hurriedly retorts he has caught the fly, but why is having a drink a punishment? I'm guessing the schoolteacher is about to cane the boy, a typical school corporal punishment in the United Kingdom. A form of punishment which in 1987 became illegal in state schools and was finally banned in public schools in 1999. In the above Wikipedia link, there is no mention of drink being a punishment or slang.

Solution 1:

Drink = experience, endure, pay the penalty. (OED drink, verb, #16).

I took this proverb to mean that a furious master will beat the pupil's hindquarters with a switch (or a cane) in any case, whether he catches the fly or not, and no matter what kind of (fancy) reply the student might give when questioned. The student has not been paying attention to the lesson but has been trying to catch flies.

Solution 2:

I'll try to flesh this out further when I have the time (others are welcome to run with it as well), but I found this explanation of Ezekiel 23:32 wherein Matthew Poole's commentary explains that "thou shalt drink," in the context of that verse, means "thou shalt not put it by, and shift it off."

So a quick interpretation of the passage would be as follows:

A boy made to catch a fly.

"Do you have it?" asked the master.

"No," said the boy. "God knows if I have."

"Then go ahead and get the fly; don't put it off," said the master.

"Oh, I think I do have it," said the boy.

"If you have it, what good is eloquent speech? Whether a boy catches a fly or not, out comes the rod for punishment."

I'm not entirely sure as to the justification for the punishment. I think "fair speeches" might refer to the phrase "God wot I"—that is, a fancy excuse or tacked-on phrase won't alter what has or has not been accomplished. (A further guess is that smacking after a fly isn't what a studious boy should be doing, so the master is saying that boys will be punished for slacking off whether or not they accomplish whatever trivial task distracted them and despite whatever grandiloquent excuses they might offer.)

This is only my intuition, however. There may be much better interpretations.