diff --git a/include/battle_ai_util.h b/include/battle_ai_util.h
index 5e66577e30..11eba7b661 100644
--- a/include/battle_ai_util.h
+++ b/include/battle_ai_util.h
@@ -5,7 +5,7 @@
 #define AI_IS_FASTER   0
 #define AI_IS_SLOWER   1
 
-#define FOE(battler) ((battler ^ BIT_SIDE) & BIT_SIDE)
+#define FOE(battler) ((BATTLE_OPPOSITE(battler)) & BIT_SIDE)
 
 bool32 AI_RandLessThan(u8 val);
 void RecordLastUsedMoveByTarget(void);
diff --git a/src/battle_ai_main.c b/src/battle_ai_main.c
index f496b90e81..af642aa8dc 100644
--- a/src/battle_ai_main.c
+++ b/src/battle_ai_main.c
@@ -486,7 +486,7 @@ static u8 ChooseMoveOrAction_Doubles(void)
                 bestMovePointsForTarget[i] = mostViableMovesScores[0];
 
                 // Don't use a move against ally if it has less than 100 points.
-                if (i == (sBattler_AI ^ BIT_FLANK) && bestMovePointsForTarget[i] < 100)
+                if (i == BATTLE_PARTNER(sBattler_AI) && bestMovePointsForTarget[i] < 100)
                 {
                     bestMovePointsForTarget[i] = -1;
                     mostViableMovesScores[0] = mostViableMovesScores[0]; // Needed to match.
diff --git a/src/battle_ai_util.c b/src/battle_ai_util.c
index 25c7f3b9d5..98fcf948a3 100644
--- a/src/battle_ai_util.c
+++ b/src/battle_ai_util.c
@@ -3248,7 +3248,7 @@ s32 CountUsablePartyMons(u8 battlerId)
     if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE)
     {
         battlerOnField1 = gBattlerPartyIndexes[battlerId];
-        battlerOnField2 = gBattlerPartyIndexes[GetBattlerAtPosition(GetBattlerPosition(battlerId) ^ BIT_FLANK)];
+        battlerOnField2 = gBattlerPartyIndexes[GetBattlerAtPosition(BATTLE_PARTNER(GetBattlerPosition(battlerId)))];
     }
     else // In singles there's only one battlerId by side.
     {
diff --git a/src/battle_anim_new.c b/src/battle_anim_new.c
index 35c1244670..0a3d433b46 100644
--- a/src/battle_anim_new.c
+++ b/src/battle_anim_new.c
@@ -6523,7 +6523,7 @@ const struct SpriteTemplate gSoulStealZStarSpriteTemplate =
 //general
 void AnimTask_IsTargetPartner(u8 taskId)
 {
-    if (gBattleAnimTarget == (gBattleAnimAttacker ^ BIT_FLANK))
+    if (gBattleAnimTarget == BATTLE_PARTNER(gBattleAnimAttacker))
         gBattleAnimArgs[0] = 1;
     else
         gBattleAnimArgs[0] = 0;
diff --git a/src/battle_controller_opponent.c b/src/battle_controller_opponent.c
index d249fc38be..8f02fb3e35 100644
--- a/src/battle_controller_opponent.c
+++ b/src/battle_controller_opponent.c
@@ -226,7 +226,7 @@ static void Intro_DelayAndEnd(void)
 
 static bool32 TwoIntroMons(u32 battlerId) // Double battle with both player pokemon active.
 {
-    return (IsDoubleBattle() && IsValidForBattle(&gEnemyParty[gBattlerPartyIndexes[battlerId ^ BIT_FLANK]]));
+    return (IsDoubleBattle() && IsValidForBattle(&gEnemyParty[gBattlerPartyIndexes[BATTLE_PARTNER(battlerId)]]));
 }
 
 static void Intro_WaitForShinyAnimAndHealthbox(void)
diff --git a/src/battle_message.c b/src/battle_message.c
index 7b263ea657..8298accf1f 100644
--- a/src/battle_message.c
+++ b/src/battle_message.c
@@ -2703,7 +2703,7 @@ void BufferStringBattle(u16 stringID)
         {
             if (gBattleTypeFlags & BATTLE_TYPE_LEGENDARY)
                 stringPtr = sText_LegendaryPkmnAppeared;
-            else if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE && IsValidForBattle(&gEnemyParty[gBattlerPartyIndexes[gActiveBattler ^ BIT_FLANK]])) // interesting, looks like they had something planned for wild double battles
+            else if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE && IsValidForBattle(&gEnemyParty[gBattlerPartyIndexes[BATTLE_PARTNER(gActiveBattler)]])) // interesting, looks like they had something planned for wild double battles
                 stringPtr = sText_TwoWildPkmnAppeared;
             else if (gBattleTypeFlags & BATTLE_TYPE_WALLY_TUTORIAL)
                 stringPtr = sText_WildPkmnAppearedPause;
@@ -2714,7 +2714,7 @@ void BufferStringBattle(u16 stringID)
     case STRINGID_INTROSENDOUT: // poke first send-out
         if (GetBattlerSide(gActiveBattler) == B_SIDE_PLAYER)
         {
-            if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE && IsValidForBattle(&gPlayerParty[gBattlerPartyIndexes[gActiveBattler ^ BIT_FLANK]]))
+            if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE && IsValidForBattle(&gPlayerParty[gBattlerPartyIndexes[BATTLE_PARTNER(gActiveBattler)]]))
             {
                 if (gBattleTypeFlags & BATTLE_TYPE_INGAME_PARTNER)
                     stringPtr = sText_InGamePartnerSentOutZGoN;
@@ -2732,7 +2732,7 @@ void BufferStringBattle(u16 stringID)
         }
         else
         {
-            if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE && IsValidForBattle(&gEnemyParty[gBattlerPartyIndexes[gActiveBattler ^ BIT_FLANK]]))
+            if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE && IsValidForBattle(&gEnemyParty[gBattlerPartyIndexes[BATTLE_PARTNER(gActiveBattler)]]))
             {
                 if (BATTLE_TWO_VS_ONE_OPPONENT)
                     stringPtr = sText_Trainer1SentOutTwoPkmn;
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index c485f40172..5c4ba2c401 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -10730,7 +10730,7 @@ static void Cmd_forcerandomswitch(void)
             monsCount = 6;
             minNeeded = 2;
             battler2PartyId = gBattlerPartyIndexes[gBattlerTarget];
-            battler1PartyId = gBattlerPartyIndexes[gBattlerTarget ^ BIT_FLANK];
+            battler1PartyId = gBattlerPartyIndexes[BATTLE_PARTNER(gBattlerTarget)];
         }
         else if ((gBattleTypeFlags & BATTLE_TYPE_BATTLE_TOWER && gBattleTypeFlags & BATTLE_TYPE_LINK)
             || (gBattleTypeFlags & BATTLE_TYPE_BATTLE_TOWER && gBattleTypeFlags & BATTLE_TYPE_RECORDED_LINK)
diff --git a/src/battle_util.c b/src/battle_util.c
index d39b03215b..1c1cf685d9 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -5817,7 +5817,7 @@ u8 AbilityBattleEffects(u8 caseID, u8 battler, u16 ability, u8 special, u16 move
         {
             if (gBattleMons[i].ability == ABILITY_TRACE && (gBattleResources->flags->flags[i] & RESOURCE_FLAG_TRACED))
             {
-                u8 side = (GetBattlerPosition(i) ^ BIT_SIDE) & BIT_SIDE; // side of the opposing pokemon
+                u8 side = (BATTLE_OPPOSITE(GetBattlerPosition(i))) & BIT_SIDE; // side of the opposing pokemon
                 u8 target1 = GetBattlerAtPosition(side);
                 u8 target2 = GetBattlerAtPosition(side + BIT_FLANK);