back to back
With backs close together or touching, as in In the first and second rows of the bus, the seats were back to back, an unusual arrangement. This term also can be applied to persons who stand facing in opposite directions and with their backs touching. [Mid-1800s]
Consecutively, one after another, as in I'm exhausted; I had three meetings back to back. [Mid-1900s]
| a stew of meat, vegetables, potatoes, etc. |
| a scrap or morsel of food left at a meal. |