Charlie stirs drinks excessively (8)
I believe the answer is:
carouses
'drinks excessively' is the definition.
Although both the answer and definition are verbs in their -s form, I don't see how they can define each other.
'charlie stirs' is the wordplay.
'charlie' becomes 'C' (phonetic alphabet).
'stirs' becomes 'arouses' (arousing is a kind of stirring).
'c'+'arouses'='CAROUSES'
Can you help me to learn more?
(Other definitions for carouses that I've seen before include "as eight [REVELLER] does" , "Engages in boisterous, drunken merrymaking" .)