Signal for bed, when eating a series of snacks (5)
I believe the answer is:
tapas
'series of snacks' is the definition.
'tapas' can be an answer for 'snacks' (type of Spanish snack). I'm not certain of the 'series of' bit.
'signal for bed when eating a' is the wordplay.
'signal for bed' becomes 'tp' (I can't explain this - if you can you should give a lot more credence to this answer).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'eating' indicates putting letters inside.
'tp'+'as'='tpas'
'tpas' enclosing 'a' is 'TAPAS'.
Can you help me to learn more?
(Other definitions for tapas that I've seen before include "Spanish savouries" , "The Spanish scoff" , "Spanish snacks" , "Small Spanish dishes" , "Spanish savoury dishes" .)