I love all the things I've been able to do with this but I have a question. This came with absolutely no instructions and I haven't got a clue how to make the Mug Attachment work. I can plug it in and get it hot but it won't clamp down on the mugs. Is there a specific size mug that has to be used? I bought generic white mugs at the Dollar Tree to experiment on and I can't get them to clamp into the attachment. I'm afraid I'm gonna shatter the mug or bust the attachment itself. Has anyone else been able to get this to work? I can't find a video anywhere that shows how this works.