Here's an idea... You have cars at the ground level of the game but they serve no purpose. There is one that appears to have a sunroof. How about you remove it (cabriolet style), and make her have car sex? She could ride the gearbox, exhaust pipe, or "dry-hump" the top of the seat. If you like the idea, you could expand it to a small gas station (or just a single pump, where she'd masturbate using a gasoline pump's nozzle or 2 for DP. Another character might get involved, the gas station operator, who would use the pumps on her.