Nemu-chan won't let me sleep! is a Manga/Manhwa/Manhua in english language, SLICE OF LIFE series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

The succubus' target was a second grader!? So begins a seductive comedy with a clumsy succubus and a mature grade schooler!