It means he's sitting by the phone, like a dumbbell... - waiting for me to call him back. - He's sitting by the phone just waiting for you to call.
זהאומר שהואיושבלידהטלפון, כמוטמבל... כן, הוא יושב ליד הטלפון ומחכהלך שתחזירלוצלצול!