It's a thought, but it's the f word (fantasies) that get's to me more than masturbation. That being said I don't like talking to my therapist about masturbation, and only have done so twice, so using a different phrase seems like a good idea. Solo sex is awesome in english, but it's not my first language and while I often shift to it in session, my therapy is generally in german. I'm gonna look out for a similar phrase in my language
How are things with you and your father?