Thanks for the responses.
Yeah that sounds OK and I'll keep playing, I might skip the sister though if that is possible, don't know yet.
Maybe romantic is the wrong word, I'm thinking of a "love" path, or whatever word you want to use, that I've seen mentioned here with the family. That is the path I want to take with the characters.
And it is my understanding that the basic serum just "unlocks" desires and lusts already held, while the drug given to Penny is entirely about making people do stuff completely against their will and they know it, with Penny clearly expressing disgust while giving the guy oral. So the basic serum is more morally "ok" than the one my MC gives Penny, if that makes sense.
Which I why I thought it was out of my MC's character to make Penny do something she clearly didn't want to. I'll just skip past that if that is really the only instance of something like that happening.