This is a rather simple adapter that you can print to attach a suction cup to a flat surface. The flat piece can then be easily attached with super-glue or E6000 to allow attaching the suction cup more easily.
I developed this Suction Cup holder to allow mounting this larger-sized cup https://amzn.to/2XRsdMr to an OpenCade http://wagnerstechtalk.com/opencade . Basically, it keeps the arcade console stationary during game play. However, I realized that this could be used for anyone wanting to mount a suction cup to pretty much anything, not just the arcade box. So, making this a separate thing for download.
You'll need to take some pliers to straighten the metal hook a little so it can slide through the 3d printed piece+suction cup. Then, simply bend it back to it's original shape to keep it secured. Works and holds perfectly fine.