In the sun, perhaps, they get a bit of a red back (5)
I believe the answer is:
nudes
'a bit of a red back' is the definition.
I can't judge whether this definition defines the answer.
'in the sun perhaps they' is the wordplay.
'in the' indicates putting letters inside.
'perhaps' indicates an anagram.
'they' becomes 'de' (I can't justify this - if you can you should believe this answer much more).
'sun' anagrammed gives 'nus'.
'nus' going around 'de' is 'NUDES'.
'get' acts as a link.
Can you help me to learn more?
(Other definitions for nudes that I've seen before include "Unclothed people" , "Dunes (anag.)" , "page-three features?" , "They wear nothing" , "They're uncovered" .)