I wanna get lost with you

I wanna get lost with you means that you and your dream lover want to sneak off together somewhere, where nobody will (hopefully) find you and, literally, for lack of better term, screw day and night.

I wanna get lost with you. Let’s go to the Northernaire Motel. Nobody will find us there. Or, even want to look there. Ahhh! Ecstasy! Bliss!