Romp dressing nearly excessively for bed (5)
I believe the answer is:
futon
'for bed' is the definition.
(type of bed)
'romp dressing nearly excessively' is the wordplay.
'romp' becomes 'fun' (romp can mean something fun or light-hearted).
'dressing' is an insertion indicator (inserted letters are dressed or clad in others).
'nearly' means to remove the last letter.
'excessively' becomes 'too' (to too great a degree).
'too' with its last letter taken away is 'to'.
'fun' going around 'to' is 'FUTON'.
(Other definitions for futon that I've seen before include "'Japanese mattress, can be folded (5)'" , "Japanese quilted mattress used as bed" , "Sleep on it" , "A Japanese bed-mattress" , "Unsprung roll-up mattress" .)