Do you think it is appropriate to use phrases like: WTF, OMFG, SHIT and etc in this game? Or do you need to be softer?
It's a smut game, any sort of self censorship would feel comical unless it's coming from a character who in character would logically be against cursing. So I could see Aisha for example scolding the MC for cursing. Or perhaps at times being ashamed at herself for uttering a curse but beyond that I don't really think most characters should give too many fucks about saying the word fuck in a game about fucking...
Now if the question is about them being overly dramatic with the exclamations then I'm thinking that should also depend on the temperament you're aiming for with the character. IE a drama queen would be more likely to shout OMFG. A calmer/ more reserved character would be less likely to shout but they might still mutter something like shit or what the fuck under their breath instead of shouting it aloud.
Oh and it would probably be better to spell the entire epithet out rather than use abbreviations unless the character in question is meant to sound like the sort of teen or bimbo that would shout out the acronym for a curse rather than saying the actual curse... So for example it might be fitting for Barbie to shout OMFG but I imagine the captain would say "What the fuck!?" Rather than "WTF".
The MC is young / immature so his cursing should probably be a bit softer or if he does have a foul mouth it should be in imitation of others cursing around him. Like for example the sex bots could perhaps start teaching him how to talk dirty to them and encourage him to use crude seemingly disrespectful language with them.
Personally I'm thinking it would be hot if perhaps as sex bots they have it baked into their core programming to have it feel good to be talked to with degrading or sexually objectifying language.
Thus the captain or Barbie could could perhaps try to encourage the MC to give them or refer to them by dirty nick names like "Sugar Tits", "Bitch Kitten", "Suck Slut", ect.
I'm thinking a really hot scene down the line could be Pamela and or Barbie putting the MC through a "sex ed" course that basically consists of having him watch porn with them while they tease / molest his cock and encourage him to repeat and or try out the stuff done in the porn.
"Mmm that's it. Cum for me like a good boy. Try calling me a cum whore if you want to see me clean all of this up for you dear."
But yeah since they're sex bots it would totally make sense if they have an inherent degree of built in masochism and or a craving for sexual degradation or humiliation. Some like Pamela might perhaps be ashamed of or try to repress the urge when acting in a position of authority. But yeah the MC could possibly be considered an outlet for indulging that programed craving. The sex bots could potentially try to raising him up towards becoming their ideal stud. I mean they already put him on Spermogen so they clearly have sexual plans for him.