Step 1: Download the official patch (0.001 MB).
Step 2: Copy "xrated.key" into the folder where the game is installed.
Step 3: Launch the game and enjoy!

You can find where Tropical Liquor is installed by right-clicking on the game in the Steam library and navigate to Properties > Local files > Browse local files. To uninstall the R-18 patch, simply delete the xrated.key file.