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How Arousal Works

In 30 seconds

  • Each actor has a single arousal number.
  • It rises when arousing things happen: seeing nudity, having sex, wearing certain armor types, being trapped in devices.
  • It falls passively over time, and drops fast after orgasm.
  • Dependent mods react when it crosses thresholds.

In a bit more depth

  • Each actor's number is the sum of all currently-active effects — both built-in (the Default plugin contributes nudity exposure, sleep decay, orgasm cooldown, denial buildup) and from any other plugin (SexLab, Devious Devices, OStim).
  • Most timed effects use game days as the time unit (one in-game day = 24 in-game hours).
  • The arousal value isn't clamped to 0–100 by default — it's just a float. The convention is 0–100 and most consumer mods assume that range, but individual effects can push outside it.

The formula

arousal = sum(static effects not in a group)
        + sum(dynamic effect values)
        + sum(effect group products)
For the full math and the timed-function table, see the author track's Overview.

The five built-in effect categories

The Default plugin ships five categories of effect, each with its own page under Plugins in the MCM. These are the knobs most players reach for:

Category What it represents Climbs when…
Naked Exposure from nearby nudity A naked (or revealingly-dressed) actor is in view — optionally requiring line-of-sight
Timed Passive "haven't had sex in a while" buildup Time passes — this is the OSL-Aroused-style tick
Sleep Morning arousal The actor wakes from a long enough sleep
Satisfaction Post-orgasm cooldown (a penalty) Resets downward after orgasm, then decays back
Legacy Boosts pushed by older mods via the ModExposure API Mods like SLEN / SL Survival fire exposure events

Other plugins add their own effects on top when their host mod is installed:

Plugin Drives
SexLab Per-stage arousal during SexLab animations, animation-tag scoring
Devious Devices Device-equipped arousal, belt/plug denial modifiers, device-stacking multiplier
OStim OStim NG (and legacy v<29) thread tracking, observer LOS arousal scaling

To see exactly which effects are active on any actor and their current values, open the Puppet Master page — see the MCM Reference.

To change how fast any of these climb, see Tuning Recipes.