The last move slot should be either Sleep Powder or Synthesis.
Sleep Powder is almost always a necessity on any Jumpluff sets. This forces the opponent to switch-out and gives you a free turn to either use a STAB move or gain momentum using U-turn.
You could also use a set-up move, such as Swords Dance.
Synthesis on this set is good for increasing Jumpluff's longevity and is reliable form of recovery. This move can work well on most Jumpluff sets because it is able to check certain Fighting-type threats and, if Jumpluff is low on health, it gives it an opportunity to either set-up or continue sweeping.
You should replace Bounce with Acrobatics because it still gets STAB and, although it has less power, it'll still do decent damage without an item. In addition, the opponent can easily switch-out while you're still using Bounce.
Contrary to what I said earlier about Sleep Powder, the move Synthesis would probably work best on your set. On the set you made, Synthesis would be the best option because it provides a reliable recovery move.
If you want Sleep Powder, you should change it to a set like Sleep Powder / Seed Bomb / Acrobatics / Swords Dance and put Focus Sash as its item. This allows it to set up Sleep Powder (if it misses or a priority move is used, the opponent can OHKO it, but Focus Sash would activate) and Swords Dance reliably.