Mixer (large) swallowed in drinking bout (7)
I believe the answer is:
blender
'mixer' is the definition.
(I've seen this before)
'large swallowed in drinking bout' is the wordplay.
'large' becomes 'l'.
'swallowed in' means one lot of letters goes inside another.
'drinking bout' becomes 'bender' (I've seen this before).
'l' inserted into 'bender' is 'BLENDER'.
(Other definitions for blender that I've seen before include "kitchen equipment" , "Kitchen device" , "Kitchen machine" , "Kitchen liquidiser" , "Kitchen appliance" .)