Effortlessly move a little son into his bed (5)
I believe the answer is:
coast
'effortlessly move' is the definition.
(as in coasting along)
'a little son into his bed' is the wordplay.
'little son' becomes 's' (abbreviation for son).
'into' means one lot of letters goes inside another.
'his bed' becomes 'cot' (type of bed).
'a'+'s'='as'
'as' going within 'cot' is 'COAST'.
(Other definitions for coast that I've seen before include "Land beside the sea" , "Cruise" , "Move easily without power" , "Where the land and sea meet" , "Freewheel - seashore" .)