For all pealing stickers, I use normal glue paste (the ones that come in the roll up tube). It is soft enough not to do damage to the plastic but able to hold the sticker in place.
I have used it with vintage, legit stickers and reprolabels with success. Reprolabels have needed the most as their sticker quality has decreased from what it used to be.
To apply, do not remove the peeling sticker but simply apply the paste evenly on the surface of the peeled portion. Make sure it is a thin even layer and not clumpy.
Then just reapply it on the plastic surface and apply pressure for at least a minute. If it's a curved surface, apply for two minutes. The sticker should remain in place by itself after that. Allow the glue to dry for an hour and that should be it.