R&B is one of the most dynamic, adventurous sounds in modern music, a place where art, both personal and provocative, meets the mainstream. From the alt vanguard to modern vets, straightforward to leftfield, these tracks capture where R&B is now and point the way to where it’s going. At the top of this week’s playlist is Up Next alum 4batz and USHER’s “act iv: Fckin U Again (18+),” a steamy ballad that finds the duo obsessing over their partners to the point that they want to keep the lovemaking going on all night long. Listen to “act iv: Fckin U Again (18+)” on R&B Now and add the playlist to your library to stay up on the latest and greatest of the genre.