Try these lines

Have you ever been in a private conversation about someone when that person comes up and wants to talk. Well you can't very well just stop talking and then look at them.(then they will know you were talking about them).

So what you have to do is quickly change the topic and the engage the oncoming person in conversation.

The following are some quick suggestions on what to say to transition out of your conversation and into theirs:


Next time try pissing out the car window.
or
I got the runs at a John Tesh concert.
or
The last time I vomited like that I couldn't eat tripe for a month.
or
And then I left a sea biscuit in the sauna and she was not happy.
or
Next time you do that stand up wind and it won't burn your eyes so much.
or
I left the $20 on the dresser and waited there until I got my change.
or
I put my Hulk underwear on today so I'm feeling quite brave but a little constricted.