Euphoria's easy running around cold street (7)
I believe the answer is:
ecstasy
'euphoria's' is the definition.
(I've seen this before)
'running around cold street' is the wordplay.
'running' becomes 'easy' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'around' is an insertion indicator.
'cold' becomes 'c' (eg on taps).
'street' becomes 'st'.
'c'+'st'='cst'
'easy' going around 'cst' is 'ECSTASY'.
'easy' acts as a link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for ecstasy that I've seen before include "Youth drug or unalloyed bliss" , "Extreme happiness" , "Delirium as from youth drug" , "Rapture; drug" , "transports" .)