The blue bed turned up inside squat (6)
I believe the answer is:
stocky
'squat' is the definition.
('stocky' can be a synonym of 'squat')
'the blue bed turned up inside' is the wordplay.
'the blue' becomes 'sky' (I've seen this in other clues**).
'bed' becomes 'cot' (cot is a kind of bed).
'turned up' says the letters should be written in reverse.
'inside' is an insertion indicator.
'cot' backwards is 'toc'.
'sky' enclosing 'toc' is 'STOCKY'.
(Other definitions for stocky that I've seen before include "Of short and solid stature" , "Strongly-built" , "Short but well-built" , "Heavily built" , "Small and well built" .)