How to feed berry

how do you feed a berry? i went to my litwick, to the three stacked lines went to give items, then went to berries,then pressed my perfect pinap berry which is bitter and wanted my litwick to eat it but instead, licwick was holding the berry which was a wrong intention. so how????

There is no perfect Pinap berry. The only perfect berries are Aspear, Cheri, Chesto, Pecha and Rawst which I believe may only be fed to a Pokemon that likes that flavor. I take it you're attempting to feed the Litwick in your party which likes spicy food. Are you trying to interact with a Pokemon? If so, you don't do that by giving it a literal item; there should be a row of the 5 berries mentioned above to click on. If there are no berries, it means it's been interacted with.