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 wordplay.
'get up' becomes 'arise' ('arise' can be a synonym of 'get up'**).
'to welcome' means one lot of letters goes inside another (in sense of 'inviting in').
'opening of' says to take the initial letters.
'twice' shows that letters should be duplicated.
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 formally", "Give notice", "Inform, make aware of", "Notify", "Inform or tell", "Inform, notify", "Tell, advise", "tip off" and "Provide with information".)