diff --git a/src/js/utilsSlave.js b/src/js/utilsSlave.js
index d20a85176e9799650b1dff25aae8814244c88c40..d28521102afe05fa5a72d11a0e6314e289215a5c 100644
--- a/src/js/utilsSlave.js
+++ b/src/js/utilsSlave.js
@@ -2111,7 +2111,7 @@ globalThis.SlaveFullBirthName = function(slave) {
  */
 globalThis.PoliteRudeTitle = function(slave) {
 	const PC = V.PC;
-	const {s, ss, title} = getEnunciation(slave);
+	const { s, ss, title } = getEnunciation(slave);
 
 	let r = "";
 	if (slave.nationality === "Japanese") {
@@ -3238,7 +3238,7 @@ globalThis.ageSlave = function(slave, forceDevelopment = false) {
  * @returns {string}
  */
 globalThis.induceLactation = function(slave, induce = 0) {
-	const {His} = getPronouns(slave);
+	const { His } = getPronouns(slave);
 	let r = "";
 	let lactationStartChance = jsRandom(10, 100);
 	slave.induceLactation += induce;
@@ -3286,7 +3286,7 @@ globalThis.induceLactation = function(slave, induce = 0) {
  */
 globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1) {
 	let r = "", skillDec;
-	const {He, his, him} = getPronouns(slave);
+	const { He, his, him } = getPronouns(slave);
 	const isleadershipRole = function() {
 		if (['headGirl', 'recruiter', 'bodyguard', 'madam', 'DJ', 'nurse', 'teacher', 'attendant', 'matron', 'stewardess', 'milkmaid', 'farmer', 'wardeness'].includes(targetSkill)) {
 			return true;
@@ -3295,7 +3295,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 	};
 
 	if (slave.skill[targetSkill] <= 10) {
-		switch(targetSkill) {
+		switch (targetSkill) {
 			case 'oral':
 			case 'vaginal':
 			case 'anal':
@@ -3311,7 +3311,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 
 		if (slave.skill[targetSkill] + skillIncrease > 10) {
 			r = `<span class="green">${He} now has basic ${skillDec}</span>`;
-			switch(targetSkill) {
+			switch (targetSkill) {
 				case 'oral':
 					r += ` and at least suck a dick without constant gagging.`; break;
 				case 'vaginal':
@@ -3325,7 +3325,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 			}
 		}
 	} else if (slave.skill[targetSkill] <= 30) {
-		switch(targetSkill) {
+		switch (targetSkill) {
 			case 'oral':
 			case 'vaginal':
 			case 'anal':
@@ -3341,7 +3341,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 
 		if (slave.skill.oral + skillIncrease > 30) {
 			r = `<span class="green">${He} now has some ${skillDec}</span>`;
-			switch(targetSkill) {
+			switch (targetSkill) {
 				case 'oral':
 					r += ` and can reliably bring dicks and pussies to climax with ${his} mouth.`; break;
 				case 'vaginal':
@@ -3355,7 +3355,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 			}
 		}
 	} else if (slave.skill[targetSkill] <= 60) {
-		switch(targetSkill) {
+		switch (targetSkill) {
 			case 'oral':
 			case 'vaginal':
 			case 'anal':
@@ -3371,7 +3371,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 
 		if (slave.skill[targetSkill] + skillIncrease > 60) {
 			r = `<span class="green">${He} is now an ${skillDec}</span>`;
-			switch(targetSkill) {
+			switch (targetSkill) {
 				case 'oral':
 					r += ` and has a delightfully experienced tongue.`; break;
 				case 'vaginal':
@@ -3385,7 +3385,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 			}
 		}
 	} else if (slave.skill[targetSkill] < 100) {
-		switch(targetSkill) {
+		switch (targetSkill) {
 			case 'oral':
 			case 'vaginal':
 			case 'anal':
@@ -3401,7 +3401,7 @@ globalThis.slaveSkillIncrease = function(targetSkill, slave, skillIncrease = 1)
 
 		if (slave.skill[targetSkill] + skillIncrease >= 100) {
 			r = `<span class="green">${He} ${skillDec}</span>`;
-			switch(targetSkill) {
+			switch (targetSkill) {
 				case 'oral':
 					r += ` and can learn nothing more about sucking dick or eating pussy.`; break;
 				case 'vaginal':
@@ -3505,9 +3505,14 @@ globalThis.randomRapeRivalryTarget = function(slave, predicate) {
  * | *-9*     | Futanari Sister       |
  */
 globalThis.addPartner = function(slave, partner) {
-	slave.partners.add(partner);
+	if (typeof partner === "number") {
+		slave.partners.add(partner);
 
-	if (partner > 0) {
-		getSlave(partner).partners.add(slave.ID);
+		if (partner > 0) {
+			getSlave(partner).partners.add(slave.ID);
+		}
+	} else {
+		console.trace();
+		throw `Partner is not a number. Type of partner is ${typeof partner}, value is "${partner}"`;
 	}
 };