Slang for consecutive life terms imposed by a judge when the defendant committed more than one crime, each of which can result in punishment of a life sentence. For example two murders, or a murder and a rape involving aggravated assault. The purpose of making the sentences consecutive ("back-to-back") and not concurrent(served at the same time) lessens the chance of parole: a life sentence really means 20 or more years in prison before parole is possible, if parole were permissible after 25 years, the defendant would then begin the second "life" sentence and would wait another 25 years for a parole hearing.