Charge about with us — excellent touring round (6)
I believe the answer is:
accuse
'charge' is the definition.
('accuse' can be a synonym of 'charge')
'with us excellent touring round' is the wordplay.
'with' becomes 'c' (I can't explain this - if you can you should give a lot more credence to this answer).
'excellent' becomes 'ace' (I've seen this before).
'touring round' is an insertion indicator.
'c'+'us'='cus'
'cus' put within 'ace' is 'ACCUSE'.
'about' is the link.
Can you help me to learn more?
(Other definitions for accuse that I've seen before include "Blame for a crime" , "Put on trial" , "Charge with wrong-doing" , "Impeach" , "Arraign or indict" .)