What does feeding a troll mean?

Feeding a troll means that when a mean person here(or any website) is constantly spamming up the site with rude コメント and/or sexual themes. If あなた keep commenting on their stuff または to them, that's what feeding means and they're only doing it for attention; therefor coming back for more. IstillkillU is a big example.

Making it a nice lunch.

it means giving what they want, attention. As long as they have that they will never go away. As soon as there're ignored they will go away.

It means reacting to a troll in a way that only makes them want to be もっと見る of a troll.

essentually it means answerring a trolls 質問 and therefore fueling their trolling

It means (on any website) commenting to a trolls rude 質問 and it keeps ranting on others.