Here's my little tip for getting those tricky slides that end in a flick:
When you're nearing the end of the slide and the flick(s) are in sight, find a spot where your phone will still register your finger on the slide and DO NOT MOVE (it doesn't have to be where the note actually ends on the slide - this is helpful for long slides). Then, when the flick finally comes, flick your fingers to the right or left or whatever your preference is.
The important thing is to NOT MOVE YOUR FINGERS a second or two before you flick. I've found that this helps the phone register the flick itself and not just the end of a slide. I also really push down on my phone when I do it and make the whole motion exaggerated (that might just be me though).
