Epel explains that his unique magic Sleep Kiss (hidden meaning: the Crimson Fruit) “encases its target in a magical barrier. The person falls asleep, but nothing outside the barrier can hurt them.”
Rook describes it as “a powerful magic force field” that “can serve as a shield for allies and a cage for foes,” saying that “the barrier’s might is an embodiment of Epel’s will power.”
There may or may not be a time limit to Epel’s unique magic: when he first learns it he says it wears off soon, and he later says it can’t last forever, but during Glorious Masquerade he says, “as long as I’m fine, Riddle will be, too,” after casting the spell on Riddle.
The day he learns the spell Epel says he finds it difficult to gauge the right coordinates for summoning the barrier and he has a success rate of only “30% to 40%,” but by Book 7 this has increased to “70% or 80% accuracy.”
We see Epel use it both during Glorious Masquerade and the Main Story and his targets do not appear to suffer any adverse side effects, with Riddle saying that he got plenty of sleep.
Twisted Wonderland Reference Note 