unholy frenzy question

[3plX]

i have this ability Unholy frenzy, i used as a dot
then i copied it and rename it, change buff, also used it as a dot

when i cast both of them on same target, they don't stack
is there a way i can make them stack?

 

[Scary Nachos]

Instead of unholy frenzy use breserk? or something close to that?

 

[bOb666777]

Or you can use Acid Bomb with no aoe