I think the only relevant "secret" you can uncover from not having sex is having your junk literally explode in one of the bad endings, if you accumulate too much cum, and do not express it. It takes a while for said accumulation to occur, but you can speed it up by taking a lot of one of the pills that build up cum, or you eat lots and lots of pickled onions. There's only one other relevant "secret", and that'd be if you had sex with the bot for a while, bonding with her, and then you withdrew from that for a while. I don't know if you need to make her horny before it triggers, but after a while, she asks you for it, and if you still don't give it to her, I think she eventually wakes you up having initiated sex with you while you were asleep. I don't think there are any other relevant points in abstaining.