I would say that if they are in an area that they can enter the nevernever from (strip club, old interrogation room, ect.), then I would imagine the best way to do it would be as an assessment/declaration to find the location's appropriate aspect, and then invoke it for effect to enter the nevernever. Or, if you don't have something planned for failure, you can just say, "Sure, you enter the nevernever from the back of the strip club."