"They are making wine."
Translation:One robią wino.
no. That sounds ridicoulus. You can't have a verb after robić. the most used word would be "kochać się" (it's a tricky one you need so much context to tell whether it means they love each other or they make love) . other is "uprawiać miłość".
(of course you know that using pronoun "one", means it's two women)
The most basic, neutral translation of 'to have sex' is 'uprawiać seks' (weirdly, the first meaning of 'uprawiać' is 'to grow' with things like vegetables. Also used for training sports). You could translate "to make love" as "uprawiać miłość", but I think the Polish phrase is a lot less common than the English one.