The way I have my thai-style cup's strings set up is bowlines on the top two strings attached with bowlines, and the middle string with a cow hitch. Currently, the way I tie it on is secure the top two strings with a square knot in front, slide the whole thing around and fumble behind my back to tie a bow with the two loose ends of the square knot for one line and the double string of the middle for another.
Most of the time this works fine for me, but occasionally I notice the groin guard manages to work loose during warm-ups. I haven't quite figured out what I do differently, but I suspect I get the bow handedness wrong and it capsizes.
So, does anyone here have a consistent method for tying a bow with my hands literally behind my back?