Halve the avocados, remove the stone, and with a spoon, scoop flesh into a bowl. Pour lime juice over, and mash roughly with a fork. Actually, a potato masher is great for this step because you get a nice chunky mash, which is what you want.
Cut peach into approx 1/4" cubes. Toss these into the bowl with the avocado
Slit the chile open lengthwise and with the tip of your knife, remove the seeds and ribs. Chop the chile finely. Depending on the size of the chile and the heat, you may wish to add only half at first to your guac. You can always add more! *You may want to wear gloves to handle the chile. If you choose not to, rub your fingers with oil or butter after handling the chiles and then wash with dish detergent
Add the remaining ingredients to the bowl containing the avocado, and using a spatula fold them in. Salt to taste and add more lime if needed.