The wraith barely even knew the Noldo, except because of his Master. He was uncomfortable around the Elf, but perhaps if he explained the issue first? No, no, better to just get it over with, then defend himself. That would be better against an aggressive force. So he knocked on Fëanor's door, and as soon as it opened he stepped inside and gave him a quick kiss.
After a brief moment of shock, Fëanor quickly regained his senses and shoved the wraith harshly away. This was followed by a hard slap, then another, and then one more.
“I don’t know what madness has possessed you,” he snarled, drawing a dagger and advancing on his unwelcome visitor. He recognised him and knew who he was, though they’d never spoken.
“Or who sent you here, but you have FIVE SECONDS to get out of my sight!”