hear that ringing?

Here's a work funny:

My boss tells me he hears a ringing sound on the phone line & that I need to call for service. so I pick up my phone (line 2) but I don't hear it. Then he says it's on line 1, don't hear it there either so I say "maybe it's in your head".

Then I'm laughing my ass off at how damn funny I am & realize I said it out loud & I'm thinking "shit, maybe that one should have been inside voice" & now I can't help but laugh even harder because I'm probably about to get fired for being such a smartass, but my boss says "yeah, I guess it might be that squirrel finally got on the wheel up there."