This is how I have mine. I carry this in my back pocket solely because I like to lift my bikes a few times senza/sans/ohne water bottles, pumps and spares just to impress myself with how light they are.
But sometimes I put in on with a toe strap too.
Too Tall is showing one good method. And his advice with the glue is to be followed. By others. If I get a flat I will nurse it home and deal with it. No fast corners for me.
I use a Sprinter because I got it free (yes, it does hold air) and because it has a butyl tube inside. And won't dry rot as fast as a Veloflex spare.
This is kept on the shelf and grabbed if I am using one of my two tubular-equipped rides here in MichMich.
My name is James Edward Kile