Fun to include a bit of tomfoolery and love on sofa bed (5)
I believe the answer is:
futon
'sofa bed' is the definition.
(I've seen this before)
'fun to include a bit of tomfoolery and love' is the wordplay.
'to include' means one lot of letters goes inside another.
'a bit of' suggests taking the first letters.
'and' is a charade indicator (letters next to each other).
'love' becomes 'o' (love means zero in tennis).
The initial letter of 'tomfoolery' is 't'.
't'+'o'='to'
'fun' enclosing 'to' is 'FUTON'.
'on' is the link.
(Other definitions for futon that I've seen before include "Japanese mattress with frame, a bed-couch" , "Japanese mattress with wooden frame used as bed" , "Padded mattress for sleeping on the floor" , "Jap. quilt bed" , "'Japanese mattress, can be folded (5)'" .)