how do I make it stay on my back making it look authentic?
I have no idea...xD
It may be very lovely if you posted reference images :x
(Not a fan of naruto so hasn`t read much but still has the knowledge regarding cosplays)
sorry, unfortunatly my computor isn't a ll that great so its hard for me to post pics... in other words.. i don't know how..
(https://forums.fanime.com/proxy.php?request=http%3A%2F%2Fwww.naruto-kun.com%2Fimages%2Fweapons%2FGourd.jpg&hash=f8987b3f0489a72b83dc068a237f47c0828e9f81)
I googled this, copied the link into my message, then added (//at%20the%20beginning%20of%20the%20link%20then) at the end of the link.
Does this help? Here's a cosplayer from the front view. Again, googled the image, hope this isn't too big to post here.
(https://forums.fanime.com/proxy.php?request=http%3A%2F%2Fwww.bansheeproductions.net%2Fconvention%2Fkatsu04%2Fimages%2Fkatsu20040030.JPG&hash=ab26072edc95fa874478dd29af26f066e6c91aeb)
Well..the cosplayer used fabric for the strap. so, you could do the same.
yeah, it's just a length of fabric.
Unless that fabric`s color is different it`s just strapped to your back dearie ^^;
yah, it's the same thing wrapped around and around~ ^__^