You may have to do what Ozone suggested.
Get the thinnest pin you can find and just touch the bubble lightly so it pierces a minute hole then press the decal down. The air will escape out the hole and your decal will stick. try piercing it where it will be less seen.
I'd be very surprised if you saw the hole after that.
A hair dryer heating the sticker up to remove again will probably only stretch the vinyl, its defo shagged then.