According to HollywoodLife, the Biritsh singer presented his T-shirt doused with his cologne to her.
"Before Selena and Niall went their separate ways for Christmas, he wrapped up one of his favorite white T-shirts and gave it to Selena to sleep in," a source said.
"She always told him how much she loves the way he smells, so he doused the shirt with his cologne. Niall told her to wear his shirt whenever she misses him. It's a super sweet gift.