That technique has a couple of different names: A sting, funk vibrato and a couple others I can't remember. It's not as easy as it looks to make it sound good. But yeah, practice is the key. Having said that, the entire bassline in the Bruno Mars tune is worthy of transcribing, (copying and learning) as it has a lot of stuff going on that can be useful in a number of R&B songs.
Last edited by Spin Doctor : 10-09-2013 at 10:29 AM.