Submissive Sex
When the player is on their knees, hostile npc's can intitiate sexual encounters with the player. These encounters last multiple turns, and as long as the npc is hostile, cannot end without the npc being satisfied, the player using their safe word, or somehow getting removed from the picture. The player can initiate multi-turn encounters with npc's on their own if they use the spread command, which will give them the option of ending things early, but there's always a chance that the player's partner becomes hostile in the middle.
Options during submissive sex
During submissive sex, the player always has the option to submit or resist. As a rule, npc's like when the player submits and don't like it when the player resists.
Submission
Submission is the default response during submissive sex. Even if the player does something that isn't explicitly submitting, such as displacing underwear or talking to their partner, they will be treated as if they are submitting.
Submission is humiliating for the player, but lets the player handle things a lot more smoothly (especially during penetration.)
Resistance
Resistance has a slightly different meaning depending on the friendliness level of the player's partner. Friendly npc's will stop having sex with the player as soon as they start to resist, but if the npc is on the verge of becoming unfriendly, resisting might turn the player's friendly partner into an unfriendly one. Unfriendly npcs won't stop fucking the player even if they resist, and if the player resists too much, they might punish the player by spanking them, tearing their clothes, and other negative outcomes. Resistance decreases the player's tolerance for soreness during penetrative sex, and during oral sex, drastically increases the chance of Gagging, both of which have a high chance of leaving the player at risk of Fainting or not being able to do anything for a turn in the middle of an encounter. Resisting also reduces the chances that the player will notice when a monster is about to orgasm.
Despite all these drawbacks, resisting allows the player to minimize humiliation gained during sexual encounters, and if the player is having unprotected sex, there may be a chance that the player can avoid a creampie or a facial if they resist at the right moment. Unintelligent NPC's also tend to care about resistance a lot less than their intelligent counterparts. Resisting is also an important part of handling sexual encounters as the Bride class.
Begging
Begging is only available as an option if the player can speak and they are having an encounter with a hostile npc. It also won't work if the npc is too stupid (like a Sex Doll) or if the npc is too mean (like a Demoness.) When it works, the player's partner(s) have a chance of being gentler with the player depending on a random number between 1 and the player's charisma. (As of version 13.10.1, there is a bug where having a charisma score higher than 1 increases the chance of begging not working.) Regardless of the player's success, begging will almost always enable the player to tell when a monster is about to cum.
Begging is even more humiliating than normal submission, and since it requires the player be able to speak, it can't be used to avoid a facial. However, if the npc is the type to actually listen to the player's begging, it's a decently reliable way for the player to avoid being creampied during penetrative sex. Certain monsters only pull out if the player begs, and certain monsters only pull out if the player resists, so it's important to pay attention.
Requested Sex
Using the spread command, the player can invite an intelligent npc to have sex with them. This still counts as submissive sex, will still be humiliating for the player, and any orgasms the player has during the encounter will still count as shameful, but the player will have control over the specific type of sex that happens and the npc doesn't need to be hostile.
Resisting during requested sex will sometimes allow the player to end the encounter early (which might be necessary if another, less friendly, npc shows up in the middle,) but if the npc doesn't like the player that much, there's a chance that the npc will decide to ignore the player's wishes and keep going anyway. Additionally, npc's won't always agree to have sex with the player even if they like the player a lot.
Submissive Sex Types
Some npc's have unique types of interactions they can have with the player, especially npc's without penises, but there are patterns that a lot of npcs follow.
Climax Warnings
The turn before an npc finishes having sex with the player, there is a chance that the player will notice that they are moving faster, their penis is "throbbing", etc. This chance scales based on intelligence, and is mainly relevant during blowjobs and penetration where the player might want to resist/beg at the last second.
Penetrative Sex
While not all npc's are up for penetration, and some prefer one to the other, vaginal and anal sex are treated mostly the same way by the game. Both the player's asshole and vagina have a stat called Orifice Soreness that increases every turn the player spends getting fucked. The player can try convincing the npc to be gentle, but even then this type of sex is the most likely to cause the player to have a shameful orgasm. Depending on the npc, the player can also lose their Virginity from this type of sex.
Creampies
If the npc has a penis, penetrative sex will usually end in the player getting creampied. During vaginal sex, this means there's a risk of Pregnancy depending on fetish choice, or an increase in Orifice Soreness if the npc's cum is somehow harmful. For anal sex, this means a risk of fainting. See Main Article: Womb and Main Article: Belly.
The player can sometimes avoid a creampie if they resist or beg right before their partner ejaculates, but each npc is different. Additionally, npc's usually won't pull out if they are in the middle of fucking the most desirable part of the player's body.
Condoms
If the npc is wearing a condom, the player will be protected from a creampie as long as they aren't unlucky enough that the condom will break or the npc will take it off last second. For certain npcs, condom breakage is more likely to break during rough sex.
Submissive Blowjobs
If they're up for it, male npc's can have the player give them a blowjob. There is no soreness stat for the player's mouth, so resisting is much less likely to make the player cum or faint compared to penetrative sex. However, fainting is still a risk because resisting increases the chance that the player will gag, and it makes the npc take longer to finish.
Oral Creampies
Blowjobs can end in the npc ejaculating into the player's mouth or straight down their thrat. If bukkake is enabled, the npc can also cum on the player's face. "Throat" creampies put the monster's semen directly into the player's stomach without giving them an option to spit it out, while "mouth" creampies allow the player to hold the cum in their mouth, spit it out, or swallow it. Spitting will usually anger or at least annoy the npc in exchange for allowing the player to avoid increases to their Semen Addiction, while Swallowing will sometimes result in the player being rewarded for their obedience, while spitting will usually anger the npc. If the player spits into a container, or they hold the cum in their mouth instead of swallowing, the npc may or may not punish the player depending on their Charisma and how much the npc likes the player.
Climax Dodging
If the player resists on the last turn of a blowjob, they will almost always avoid the npc cumming straight down their throat (unless the player is currently deepthroating them, which makes it unavoidable.) Sometimes npcs will decide to finish in the player's mouth by themselves, but it depends how much they like the player. If bukkake is enabled, resisting gives the player a chance to dodge a facial at the last second.
Default formula that npc's use to determine whether to finish in the player's mouth instead of finishing down their throat:
unfriendly_limit = the number of favor points where monster becomes unfriendly, usually 10. For some slut school npcs its 12.
mouthful_chance
= 5 + unfriendly_limit
Based on this number, a random number between 0 and mouthful_chance
is rolled, and if that number is lower than the npc's friendliness score, the npc will finish in the player's mouth.
Titfucks
If the npc is willing, has a penis, and the player's breasts are at least DD cup, the npc can have the player give them a titfuck. During this type of sex, resisting has fewer drawbacks compared to blowjobs or penetration (aside from making it last longer), but it also has fewer upsides, since titfucks almost always end in the same way -- with a facial. If bukkake isn't enabled, it won't even leave a mess.
Repeatedly performing titfucks to completion will increase the sensitivity of the player's chest over time, so while the risk of orgasm from boob stimulation is low at first, the player can eventually find themselves cumming just from moving their breasts.
Penis-Based Sex
If the player has a penis, certain npcs can initiate some penis-based play. Usually, this "play" involves the npc mounting and riding the player, which will take the player's Virginity, but there are exceptions.
If the player doesn't have an erection, and is unable to get one on command (or at all,) they will be punished. This type of sex also won't end the virgin curse if the player has it, as only dominant sex can do that.
Licking/Tongue Worship
If Grossness Fetish is enabled, and the npc is willing, they can have the player lick their feet or lick their balls. This is different from submissive blowjobs or cunnilingus, as the npc usually isn't able to cum during these types of scenes, and the player will be grossed out slightly each turn. It is a form of oral sex, and is therefore not possible if the player is gagged.
Anilingus
If Ass to Mouth Fetish is enabled, and some npc's may elect to have the player eat their ass instead. They may even prioritise this depending on the level of Grossness Fetish enabled.