How can you safe and sound fix a leather bolster cushion to top of leather sofa? I've got myself a unmarked sofa but it's very low pay for....

I've got myself a unmarked sofa but it's very low pay for. I also have equivalent foam tube shape bolsters which would look a treat on the top of the backs of the sofa, so they achievement as head rests. Problem is, as the bolsters are cylindrical, how can I fix this to the spinal column. It needs to be out of harm`s way and any fixings need to be unnoticed. I can take the foam out of the bolsters so no problem next to making holes etc, but I can't get my foot underneath the leather of the actual sofa back. Please back, been racking my brains for 6 months!
Leaking mower??
Answers:    may nouns drastic but if it is to be permanant then you could use a staple gun to fix a piece of cloth near either buttons or a fastener onto the back of the couch and after sew the matching bit onto the bolster cushion, excluding staples you can buy semi circle needles so you could sew it on instead, it sounds a bit strange but it is the only passageway I can think of and not a soul else had answered when I started to type so someone have probably come up with a easier one by presently,
Good luck with it.
Looking for plastic sheeting of at lowest possible...
you can catch strong sticky backed velcro that should do the trick