Talk fondly about a type of 'booze train' (4-4)
I believe the answer is:
choo-choo
'train' is the definition.
(I've seen this before)
'talk fondly about a type of booze' is the wordplay.
'talk fondly' becomes 'coo' (as in cooing to a baby).
'about' means one lot of letters goes inside another.
'a type of booze' becomes 'hooch' (type of alcohol).
'coo' placed around 'hooch' is 'CHOO-CHOO'.
(Other definitions for choo-choo that I've seen before include "Baby train?" , "Child's word for train" , "(Childish) train" , "A baby's train" , "Child's railway train" .)