In a tall glass add the sliced peaches. Add the peach-infused gin and lime juice. Top with the tonic and more ice to fill the glass. Stir to combine. Garnish with a twist of lime.
Combine the gin and peach chunks in a bowl and smash the peaches. Allow the mixture to sit for 2 hours or up to 24 hours. Strain the mixture and store in a covered jar in the refrigerator.