Cheeks blushing still, you adjust minuscule bikini finally (6)
I believe the answer is:
glutei
'cheeks' is the definition.
(buttock muscles)
'blushing still you adjust minuscule bikini finally' is the wordplay.
'finally' says to take the final letters.
The final letters of 'blushing still you adjust minuscule bikini' are 'GLUTEI'.
(Other definitions for glutei that I've seen before include "behind?" , "muscles" .)