Tell to get up to welcome opening of presents twice (7)
I believe the answer is:
Here is my best explanation:
'tell' is the definition.
'get up to welcome opening of presents twice' is the subsidiary indication.
'get up' becomes 'arise' ('arise' can be a synonym of 'get up'**).
'to welcome' indicates putting letters inside (in sense of 'inviting in').
'opening of' suggests taking the first letters.
'twice' says to double the letters.
The first letter of 'presents' is 'p'.
'p' doubled is 'pp'.
'arise' going around 'pp' is 'apprise'.
'to' is the link.
(Other definitions for apprise that I've seen before include "Inform, make known to", "Inform, notify", "Give notice", "Tell, advise", "Inform or tell", "Inform formally", "Inform, make aware of", "Notify", "Provide with information" and "Give information to".)