Prevent SlideIn From Showing Again if Visitor Ignores the SlideIn

Is it possible to just have the SlideIn show just once without the visitor having to manually close the SlideIn window? Basically, if the visitor ignores the SlideIn, and the SlideIn eventually slides out, I'd like for the visitor to be able to navigate throughout the website without the SlideIn showing up again. Basically, I'm asking if there is a way for ignoring the SlideIn to have the same effect as clicking the "X" and closing the SlideIn. Thanks!