Not a fully-blown NSFW game, but Cover Yourself mod for Oblivion may be a good idea. Unfortunately the "fine" you get for walking around naked is not customizable, just 5 golds, which is hard NOT to have around (and ain't nobody asking where you were carrying those, money don't smell, ok?) but if you actually don't (or opt not to pay) you'll be sent to jail. Another problem of the mod is that clothes are overabundant in the game, it's not like you may happen naked against your will, but you need to actively reject the opportunity to get dressed to get any ENF fun. Also most likely there are some NSFW mods for prisons (Skyrim does for sure; it also has Indecently Exposed mod which is kinda supposed to do the same, but overall this game is not that suited for ENF, unfortunately).
