The most common and most likely answer to this crossword clue is the 8 letter word MAYPOLES
I've seen this crossword clue in The Guardian
M
A
Y
P
O
L
E
S
More clues leading to the result MAYPOLES
Buddy explains!
The straight part
We know that "Festive erections" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case festive erections = maypoles.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 MAYPOLES mean?
MAYPOLES noun- A pole, garlanded with streamers held by people who dance around it to celebrate May Day.
- A maypole-like structure of sticks placed about a sapling in the bowers of certain species of bowerbird.
- A penis, especially a large one.