Tip: before adding the interaction, gate it with a "let us keep npcs from spamming this" interaction.
[CDI:USAGE_HINT:ATTACK]
[CDI:TARGET:SELF_ONLY]
Have that interaction apply a syndrome which lets you breathe fire or whatever, but uh, make sure you put [FIREIMMUNE_SUPER] on at least the caste you're adventuring with, it can't be added with a syndrome and you will get caught in your own breath regularly.
In interaction_standard.txt at the bottom add this:
[INTERACTION:CONTROL_RAGE]
[I_TARGET:A:CREATURE]
[IT_LOCATION:CONTEXT_CREATURE]
[IT_CANNOT_TARGET_IF_ALREADY_AFFECTED]
[I_EFFECT:ADD_SYNDROME]
[IE_TARGET:A]
[IE_IMMEDIATE]
[SYNDROME]
[CE_CAN_DO_INTERACTION:START:0]
[CDI:ADV_NAME:Enrage]
[CDI:INTERACTION:ENRAGE]
[CDI:USAGE_HINT:ATTACK]
[CDI:TARGET:A:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:A:15]
[CDI:VERB:enrage others:enrages others:NA]
[CDI:WAIT_PERIOD:5]
[CE_CAN_DO_INTERACTION:START:0]
[CDI:ADV_NAME:Breathe fire]
[CDI:MATERIAL_EMISSION]
[CDI:USAGE_HINT:ATTACK]
[CDI:BP_REQUIRED:BY_CATEGORY:MOUTH]
[CDI:FLOW:DRAGONFIRE]
[CDI:TARGET:C:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:C:15]
[CDI:MAX_TARGET_NUMBER:C:1]
[CDI:WAIT_PERIOD:50]
[INTERACTION:ENRAGE]
[I_SOURCE:CREATURE_ACTION]
[I_TARGET:A:CREATURE]
[IT_LOCATION:CONTEXT_CREATURE]
[IT_CANNOT_TARGET_IF_ALREADY_AFFECTED]
[IT_MANUAL_INPUT:rage targets]
[I_EFFECT:ADD_SYNDROME]
[IE_TARGET:A]
[IE_IMMEDIATE]
[SYNDROME]
[SYN_NAME:being enraged]
[CE_FLASH_TILE:TILE:19:3:0:0:FREQUENCY:2000:250:START:0:END:480]
[CE_FEEL_EMOTION:EMOTION:HATRED:SEV:1000:PROB:100:START:0:END:480]
[CE_FEEL_EMOTION:EMOTION:RAGE:SEV:1000:PROB:100:START:0:END:480]
[CE_FEEL_EMOTION:EMOTION:ANGER:SEV:1000:PROB:100:START:0:END:480]
[CE_REMOVE_TAG:CAN_LEARN:START:0:END:480]
Under the creatures you want to be able to do butcher/consume sapients, add this after the spit interaction:
[CAN_DO_INTERACTION:CONTROL_RAGE]
[CDI:ADV_NAME:Control Rage]
[CDI:USAGE_HINT:ATTACK]
[CDI:TARGET:A:SELF_ONLY]
[CDI:TARGET_RANGE:A:1]
[CDI:WAIT_PERIOD:30]
If you want fort mode units to do it, remove the brackets around the: CDI:USAGE_HINT:ATTACK line.
I just happened to have part of this handy, it's my "can use and eat sapient materials" interaction with the dragonfire tossed in, and the gating interaction to keep npcs from spamming it.