I would ask writers Game masters and gamers to use the item in their stories/games and see what uses they come up with i would never thought of on my own
Whike waiting for that to come to fruition ide look for a passable look a like to team up with.
Then i would figure out how the teleporting works. If it maintains speed/velocity/vector/momentum
test if i could jump from really high, pop into my pocket dimension just before hitting the ground cancelling out the speed i was falling when i pop out of the pocket dimension