I booked a girl about 20 years ago who I realised was an old school friend's older sister. Not seen each other in a few years even then. I never fancied her, to be honest. I sussed it was her straight away but despite some quizzical looks I don't think she was sure. Though I think the penny dropped when she went down on me. Not that she'd ever seen my cock before. Suddenly she went bright red and got a bit flustered, and started looking away. Like she was trying to hide her face even though we were about to have sex. I can't deny it added a thrill. I ended up going to town- RO, 69, several positions, and finished up cumming over her tits and chin. The last few mins as i got dressed and she cleaned herself up were excruciating. She could barely speak or look at me. Hadn't seen her brother forever, and never saw him or her again.