This is a somewhat crazy idea that actually is useful. Occasionally I like to sit upright on my bike without bending over to hold onto the handlebars - but I don't like to ride "no hands" - which is strange because I do like to ride a unicycle. So got this idea to make some reins and surprisingly they work quite well.
Of course you have to be careful, it is potentially dangerous and you have no brakes - kind of like riding a unicycle.
Step 1: Cut Ends Off Bungee Cord
I used a hard rubber core bungee cord that does not stretch easily. The length is about 120 cm. Cut the ends off and burn the nylon coating on the ends to keep from unraveling.
Then use will need some stiff wire for the next step.
Step 2: Form a Loop at the Ends, Wrap With Wire and Tape
I folded over a loop of about 20 cm of the bungee cord. Then wrap the loop together with stiff wire. I had some heavy magnetic wire for this talk.
Then tape with duct tape. You do not want the ends coming apart while you are riding.
Step 3: Mount on Handlebars and Go Riding.
The final product is about 70 cm long.
Loop the two ends over the ends of handlebars and you are ready to use.