For SlashDash'd, SlashDashALot, Deforestation, Jounin, Bragging rights, and Backscratcher start up a match of CTF on Phantom Island. To start off, take your teammate and grab the enemy flag. Wedge him into a corner and hit him with
so that he stays in the corner. Keep spamming slash until you've unlocked SlashDashALot, which will unlock SlashDash'd now, and Back Scratcher at the end of the match.
Check your achievement tracker and see where Jounin is at %-wise toward 100. This will tell you how many kills you've gotten this match once it unlocks. For instance, if it's at 70% when you start the match, then you will have gotten 30 kills when it unlocks. Keep that in mind so you know how many more kills you need to get 50 by the end of the match.
Proceed over to the enemy spawn and stand between them. Move the enemies next to you up against each other and kill them both with one slash for a double kill (large log, two small logs is not a double kill). Do this 5 times total for Deforestation. Continue killing the enemies until you've unlocked Jounin, and any additional to make sure you've gotten 50 kills total this match for Bragging Rights.
You can see these achievement setups in action starting at
5:24 in the video below.