It's heavenly for me to be in bed (5)
I believe the answer is:
comet
'it's heavenly' is the definition.
I can't judge whether this defines the answer.
'me to be in bed' is the wordplay.
'to be in' is an insertion indicator.
'bed' becomes 'cot' (cot is a kind of bed).
'me' put inside 'cot' is 'COMET'.
'for' is the link.
Can you help me to learn more?
(Other definitions for comet that I've seen before include "Object in space with bright centre and long hazy tail" , "Early jetliner" , "Frozen body" , "Halley's space traveller?" , "astronomical sight" .)