While taming, after eating a cake, the bar will read "place food in inventory to tame" even though you have cakes there. Also, the torpor score goes up quickly from feeding narcs, different from other tames
If you are considering breeding these, go slam your hand in a car door a few times. It will be much less painful. Literally one veggie cake per percent of growth....and it grows slow.. Digests roughly one point of food per second, so feed a cake about one for every 7 mins (during event boost) and it will gain one percent of growth.