Lecherous desire, touching below! (6)
I believe the answer is:
wanton
'lecherous' is the definition.
(thesaurus)
'desire touching below' is the wordplay.
'desire' becomes 'want' ('want' can be a synonym of 'desire'**).
'touching' becomes 'on'.
'below' means one lot of letters go next to another.
'want'+'on'='WANTON'
(Other definitions for wanton that I've seen before include "Reckless" , "uncalled-for" , "Thoughtlessly and unnecessarily cruel" , "Libertine" , "Irresponsible, lacking proper restraint" .)