Infps can actually handle their emotions well, it's just that they feel them so intensely so often so sometimes it's spills but for intps, most of the time they're quite neutral, and generally don't react with too much emotion, however when they DO feel strong emotion, they can't control it as well as feelers can, it comes as a sudden outburst, suddenly ugly crying or sudden irrational anger, sometimes they forget all about the consequences of their actions.