jac-fuck
A Jac-fuck is when you’re trying to get your rocks off, and your girlfriend decides to join the fun, even though she didn’t ask.
I was getting to the good part when my girlfriend just walked in and started watching with me.
I was about to climax when my girlfriend walked in and said, 'Hey, wanna do this together?'
I was getting my jollies when my girlfriend showed up and said, 'Why are you watching this alone?'