Edit: Oops! Nevermind, I found my answer in another comment lol! I'll just leave my comment and the answer here in case anyone else goes looking.
My previous comment: [Hello! I've a question. In the screenshots I see we have a "Sit in his lap" option but I can't seem to get it? Help plz?]
Answer: To get the 18+ scenes you gotta have sex with Ren the first night