Where is that cellphone, anyway?

So, the other day I was calling someone on my cellphone, and while I was listening to it ring, I headed to the bathroom to relieve myself.  As I eased onto the seat, I noticed my empty cellphone holster on my waistband.  "Damn," I thought, "I've misplaced my cellphone again!" 
Or, it could just be in my other hand, next to my ear, still listening to the ringing.