It may be just an excuse to stay in bed (3)
I believe the answer is:
lie
'stay in bed' is the definition.
'lie' can be an answer for 'stay'. I am not certain of the 'in bed' bit.
'it may be just an excuse' is the wordplay.
I cannot really understand how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found within the answer.
'an' could be 'i' (Roman numeral for one) and 'i' is present in the answer.
A single letter 'l' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for lie that I've seen before include "Perjure" , "Perversion of the truth" , "Equivocate" , "Whopper" , "Rest; deception" .)