Porter, say, coming across well time after time, making splash (9)
I believe the answer is:
bespatter
'splash' is the definition.
(I've seen this in another clue)
'porter say coming across well time after' is the wordplay.
'porter say' becomes 'beer' (porter is a type of beer).
'coming across' indicates putting letters inside.
'well' becomes 'spat' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'time' becomes 't' (abbreviation).
'after' is a charade indicator (letters next to each other).
'spat'+'t'='spatt'
'beer' going around 'spatt' is 'BESPATTER'.
'time making' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
(Other definitions for bespatter that I've seen before include "Defame" , "Spray with droplets" , "Dirty" , "Make mess of" .)