As described

Like it was described in Eat, Pray, Love:

It's when someone decides to power you with a dosage of attention, needy, gushing attention. It's like dangling a carrot over your lips, coated with chocolate and goodies. It's a bait, a drug, soon to be your everything. Soon you start craving that attention, and when the drug is withdrawn, you get listless, sick, emotional. You want more. But now that someone doesn't want to give it to you, even though he knows he can. You get cravings and wants and now he's repulsed by you, he doesn't acknowledge you, much less is in love with you. You may devalue yourself and find yourself doing odd things never thought of. Just to get a bit more of it. And there you go.

As aptly put in SKK:

It's when you want to see this person over and over again, you can't get enough. Whatever happens with this person, you feel either extremely happy or miserable. But you still want more. You can't forget, you think about it all the time, you reminicise, you practically pulse faster.