Manipulate body with maturity (7)
I believe the answer is:
massage
'manipulate' is the definition.
(massaging is a kind of manipulating)
'body with maturity' is the wordplay.
'body' becomes 'mass' (mass is a kind of body).
'with' says to put letters next to each other.
'maturity' becomes 'age' (I've seen this in another clue).
'mass'+'age'='MASSAGE'
(Other definitions for massage that I've seen before include "Rub to relieve pain" , "Relaxing treatment" , "Relaxing manipulation" , "Present favourably" , "Manipulation of the muscles" .)