Okay so I was 99% sure of it but now I'm EXTRA sure of it with the second ending. That's super hot. Hypno GF is a liar. She's probably got you caught in a loop of forgetting and remembering that you're her bf and nothing of the sort ever happened at all and she just comes over for a romp and some food when she's able.
She definitely was using her own coin as a means to get you to accidentally trance yourself. That's why she needs you to keep going. It's not about the coin's power, it's about the technique, and the technique is working on you yourself, not her.