Spray tack is a great tool. Especially with fabric items. You can purchase spray tack at almost any craft, home improvement or department store. Spray tack is Repositionable Spray Adhesive. It generally runs about $5 a can. Krylon makes one called Easy Tack. Elmer’s and 3M also make their own versions. Just make sure the can says Repositionable Spray Adhesive.
You use it on things such as shirts and mouse pads. Sometimes when you try to do fabric items, when you lift the press, the paper can shift, causing a "ghosting" effect of the image on your product. What has happened was when the paper shifted, the sublimation process continues since the product is still hot; there are still some remaining dyes on the paper, and you get a second image slightly off kilter from the first image.
Now, the important stuff. How does it work? Well, here you go. Print out your transfer as normal. Then take your transfer and hold it up, and very lightly spray the spray tack directly onto the image. I want to highlight very lightly. It does not take much. Also, do it in a different area or room if possible. Some of the mist can move around in the area and settle on equipment, so be careful. Then, if you are doing mousepads, set your image face up, and center your mousepad onto the image. It will stick in place. You can then press the mousepad as normal. When it is done, the paper will be lightly tacked into place on the mousepad. Remove it, and you are done. If you are doing a shirt, place your shirt on the press as normal, and place the transfer onto the shirt in the correct place. It will stick to the shirt. Press as normal, and when you open the press, it will remain tacked in place. Remove the transfer, and you are done. The tack should not affect the image quality at all if you did not overdo it.
Have more questions about sublimation, spray tack or avoiding sublimation issues? Check out this sublimation Q&A!