I usually rig a bridle with my line that has a clip on the bitter end. I get a
line from the towee, attacherd to something he wants towed, snap it on my clip
and give him the bitter end of his line to secure in an accessible position on
his boat. Then when he decides we have towed long enough, has an emergency or
otherwise needs to break the tow he can just release his end of the line, it
pulls through my clip and he is free. With a very small amont of coaching I
can usually pull them up to a dock, release the tow and be on my way without
any further exchanging of line.
The only trick for me is keeping my line out of my prop but that is really my
problem.