You must stop frenzied stampede ... excited? (7,2)
I believe the answer is:
steamed up
'excited?' is the definition.
(thesaurus)
'you must stop frenzied stampede' is the wordplay.
'you' becomes 'u' (commonly used in online communication).
'must stop' indicates putting letters inside (stopping can mean blocking a gap).
'frenzied' is an anagram indicator.
'stampede' with letters rearranged gives 'steamedp'.
'u' put inside 'steamedp' is 'STEAMED UP'.
(Other definitions for steamed up that I've seen before include "Annoyed" , "Indignant (colloq.)" , "window being so opaque" , "in a stew" , "Mad" .)