Alien runs back and forth to queen, in a wobble (6)
I believe the answer is:
teeter
'wobble' is the definition.
(I've seen this in another clue)
'alien runs back and forth to queen' is the wordplay.
'alien' becomes 'et' (extra terrestrial).
'runs back' says the letters should be written in reverse.
'and' says to put letters next to each other.
'forth' becomes 'ete' (I am not sure about this - if you are sure you should believe this answer much more).
'to queen' becomes 'r' (abbreviation for regina, e.g. in ER ).
'et' written backwards gives 'te'.
'te'+'ete'+'r'='TEETER'
'in a' is the link.
Can you help me to learn more?
(Other definitions for teeter that I've seen before include "Hesitate on the brink" , "Wobble as though about to fall" , "Sway back and forth on the edge" , "Sway back and forth, on the brink perhaps" , "Wobble on the brink" .)