Sentence:  It wouldn't work with you... <WSD>Sex</WSD>, I mean. You're... easy to be with. You're... you're not dangerous. You're my best friend, John. I couldn't have it on with my best friend, John. It would be embarrassing. Sorry. Honest. 
Meaning of the word marked with <WSD> tags:  Sexual activity, "usually" sexual intercourse "unless preceded by a modifier".