The most common and most likely answer to this crossword clue is the 6 letter word GLUTEI
I've seen this crossword clue in The Guardian
G
L
U
T
E
I
More clues leading to the result GLUTEI
- More than one muscle in climbing that is supporting an excessive amount
- Cheeks blushing still, you adjust minuscule bikini finally
- They’re in behind tooth, primarily cutting gum with one
- Contractors put cement around front of traffic island
- I get Nuala regularly playing cheeky parts
- Instrument poking Joe’s cheeks
- Individual overcome by Bond clenching tense buttocks
- SEAT components in plenty unveiled at centre
- Stuff that’s put back behind
- Joe hides music player behind?
Buddy explains!

The straight part
We know that "cheeky parts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cheeky parts = glutei.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 GLUTEI mean?
GLUTEI noun- One of the several muscles of nates, which arises from a pelvis and inserted into a femur.
- Short for gluteus maximus, the large muscles in the human buttocks.