... guide one has in bed (5)
I believe the answer is:
pilot
'guide' is the definition.
(pilot can mean a navigator)
'one has in bed' is the wordplay.
'one has' becomes 'lo' (I can't explain this - if you can you should believe this answer much more).
'in' indicates putting letters inside.
'bed' becomes 'pit' (I've seen this in other clues).
'lo' inserted into 'pit' is 'PILOT'.
Can you help me to learn more?
(Other definitions for pilot that I've seen before include "Small flame that ignites a gas boiler" , "Ship's guide" , "Aircraft captain" , "He steers ship or plane" , "This person can be found in a plane or a boat" .)