The most common and most likely answer to this crossword clue is the 12 letter word AFTER-SCHOOL
I've seen this crossword clue in The Guardian
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Buddy explains!
The straight part
We know that "following lessons" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case following lessons = after-school.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does AFTER-SCHOOL mean?
AFTER-SCHOOL adjective- Taking place immediately after school classes.
- Of or pertaining to a program intended to care for and educate children in the time immediately after school classes.