Go right off sex service trade. It's too much! (9)
I believe the answer is:
excessive
'it's too much' is the definition.
(I've seen this before)
'go right off sex service' is the wordplay.
'go' indicates anagramming the letters (I've seen 'went' mean this ('go' can mean move)).
'right' becomes 'R' (common abbreviation).
'off' is a deletion indicator.
'sex'+'service'='sexservice'
'sexservice' with 'r' taken out is 'sexsevice'.
'sexsevice' is an anagram of 'EXCESSIVE'.
'trade' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for excessive that I've seen before include "Beyond normal limits" , "Inordinate, unreasonable" , "More than is desirable" , "Disproportionate" , "Too much" .)