Run qemu from USB - no install on host o/s?

[Mr Chip]

Is it possible to run qemu without installing on the host system?  I remember years ago (I think it was boot2disk) that had qemu baked in that would let u test an iso but qemu was not installed on the hsot o/s.  

I'm wanting to put qemu on a thumb drive and run it off of that without installing on the host.  This way if I go to a friends or cafe computer nothing is installed and I can run my distro off the thumb drive without booting from the usb?

I did check portable apps but that was old links to 2012.  The manual talked about loading in memory but I think Im down the wrong rabbit hole.

How do I run qemu from a usb stick without installing on the host o/s?

Thanks