I was 16 years old and had a knockout blond 9 girlfriend.
She and a friend came over, and the three of us ended up hanging out in my bedroom. Everything was blah, blah, yak yak yak... the three of us had the whole house to ourselves for the night. Well, eventually my gf's friend gets up off my bed... Oh yeah, they were both on my bed and I wasn't. So, she gets up off my bed and comes over and sits on my lap facing my girlfriend.
So we were chatting and joking... and the girl in my lap reaches behind her back and starts rubbing my dilznick. I was shocked and the only thing I could think of is "what if my girlfriend finds out!?!" The girl in my lap is smiling at me, rubbing my junk, chatting and smiling at my girlfriend - who is smiling back.
Being a novice, the 3-way possibility only flickered through my mind, then I went back to "what if my girlfriend finds out!?!" I ended up ushering the girl off of my lap because I was about to spluge, and the night ended abruptly afterwards with no one getting any.
After I replayed that whole scene over in my head a buh-zillion times, I started to pick up things that I didn't notice at the time because of the shock. There were some silences in which my gf on the bed was smiling at the girl on my lap. No big deal, except her arm was blatently jacking up and down... and the *scritch, scritch, scritch* noise of the clothes rubbing. It makes me sick to my stomach to think about it. All I had to do was get up and turn out the lights.