Out of curiosity I looked at the code. You can look for yourself in the file www/js/plugins/RemtairyKarrynOnani.js
You have 4 noise levels, all of which are indicated in the text at the top left of your screen:
JavaScript:
const InvasionNoiseLevelOneEN = "\\C[8]Faint noises can be heard outside.";
const InvasionNoiseLevelTwoEN = "\\C[7]Faint movement can be heard outside.";
const InvasionNoiseLevelThreeEN = "\\C[2]Inaudible talking can be heard outside.";
const InvasionNoiseLevelFourEN = "\\C[10]Someone is shouting outside.";
const InvasionBattleStartEN = "A bunch of people barge into the room!";
It handles the noise levels like this:
JavaScript:
let invasionChance = this.getInvasionChance();
let invasionNoiseLevel = this.getInvasionNoiseLevel();
let invasionNoiseLevelEffect = Math.max(invasionChance * VAR_NOISE_LEVEL_INVASION_CHANCE, VAR_NOISE_LEVEL_MIN_EFFECT);
//minimum effect is set at 4, the other one is 0.2
if(invasionChance > 0)
invasionChance += invasionNoiseLevel * invasionNoiseLevelEffect;
if(invasionChance > 0 && Math.randomInt(100) < invasionChance) {
$gameSwitches.setValue(SWITCH_INVASION_BATTLE_ID, true);
this._startOfInvasionBattle = true;
So what this basically does: it adds a certain value to the invasion chance you saw at the start of the masturbation scene. This added value is the product of 4 or higher and the noise level (the text you saw in the top left corner). Example: 30% invasion chance at masturbation start turns into (30 + 6 * 3 ) = 48% invasion chance if your noise level is 3 (the 6 in this calculation comes from 0.2 * 30 from the Math.max expression).
As for your question: with decent energy and low pleasure damage you're looking at a 8-12% increase of the invasion chance IF your initial value is higher than 0%. A 0% starting value remains 0.