Most likely you're not doing anything by pressing on the scanner. That shouldn't fix anything; BUT(!)... by standing in front of the scanner, or placing your hand near the top of the scanner, you may be blocking some signal from getting to the antenna, making it easier for the scanner to decode the simulcast system. Turning the scanner on the side, making the antenna horizontal, will reduce the signal as well.
Try putting your antenna all the way down, and turning it horizontal, so that it's hidden behind the scanner, and see how that does. That should reduce the signal as well.
The simulcast issue happens because your scanner is receiving more than one signal on the same frequency at nearly the same time (milliseconds apart, creating confusion (unintelligible audio) within your scanner).
To fix that issue, you need to try to receive only 1 of those 5 signals in Madison county. To do that you need to reduce your antenna so you receive less signal. You could try making the antenna as small as possible and folding it behind the scanner; you could try taking the antenna off entirely; or try taking the antenna off and putting a paperclip or a small piece of wire into the center of the scanner's antenna connector. The purpose is to make the antenna so small that it only receives the closest radio tower to your house. At that point, everything you hear from the P25 system should be intelligible.