I tried a lot of different methods, but this one worked for me like a charm:
My Button Layout: Press start and go to controller settings (if you did not change your button layout it is the same as mine, with the only exception being
= TAG
= LP
= RP
= RK
=
+
+
; this is the most important set up for an easier achievement
OK, now let's fight:
First Fight: Press
+
and a millisecond after
(this will throw your enemy into the air and change to your Tag-partner)
now just keep spamming: 3x
and 2-3x
--> rinse and repeat ( of course there are much better combos, but I am quite bad at this, so I keep it simple :) )
As soon as the enemy starts to flow: just press
and then keep going with 3x
and 2-3x
Second Fight: Press
+
(to throw the enemy into the air)
and now Press
(this performs the assault automatically)
now just keep spamming: Hold
and press 3x
and 2-3x
As soon as the flowing part starts again, repeat like in round 1
Last fight: Is a rinse and repeat of the first round and actually does not need any other description.
Hope it helps some of you, as much as it did help me. Good Luck :)