Flies lower, right into drink (7)
I believe the answer is:
diptera
'flies' is the definition.
(I've seen this before)
'lower right into drink' is the wordplay.
'lower' becomes 'dip' (dipping is a kind of lowering).
'right' becomes 'r' (common abbreviation).
'into' is an insertion indicator.
'drink' becomes 'tea' (tea is a kind of drink**).
'r' inserted into 'tea' is 'tera'.
'dip'+'tera'='DIPTERA'
(Other definitions for diptera that I've seen before include "Flighty little types" , "Insects" , "Flies" .)