I saw this design on a folding bike and thought it awesome. I used to hitch my bike trailers with a lashed inner tube, but this is faster and more convenient. Works very nicely.
Step 1: Obtain necessary hose and pneumatic release components.
1 x male 3/8"
1 x female 3/8"
1 x 3/8" threaded coupling.
hose to fit tight on 3/8"
2 x hoseclamps
Step 2: Place hose over pneumatic fitting
screwing it on worked well.
Step 3: Secure with hose clamp
Step 4: Same for both male and female coupling
Step 5: Drill hose in appropriate places for attaching to frame
Step 6: Make frame attachment (on pannier rack)
Step 7: Attach hose to pannier rack
Step 8: Attach hose to trailer handle
PRETTY SELF EXPLANATORY THIS ONE...
Step 9: Ride happily away to the store to carry buckets of stuff.