get off with (someone)

1. Literally, to disembark (e.g., from a vehicle, elevator, etc.) with someone. I ran into George on the bus and decided to get off with him at his stop in town. The CEO had me get off the elevator with him because he wanted to hear more about my idea for revamping the department! A: "Are you getting off the train with me?" B: "Sorry, no, I'm going all the way into the city."

2. slang To have an amorous or sexual encounter with someone. Primarily heard in UK. We weren't at the club for more than 30 minutes when Jake got off with some girl he had just met. I heard Janet got off with one of her co-workers at the Christmas party last night. Those two were flirting all night, so I'm not surprised to hear they got off with each other.