manip = "cheating" the pattern by hitting it not as you supposed to, not much else to say.
jumptrilling rolls, or hitting a onehand trill as a jumpjack is probably the most basic manip. and even though you can't always hit them or other patterns properly because of bpm, I'd recommend focusing on the files/rates that you actually can hit properly at least for the most part, because by manipulating all the time you don't really develop anything besides, well, manipulation skill. your technical skill (which is roughly acc and stability) would be much better from playing properly.