Print:

King's Toilet Bowl Top
King's Toilet Bowl Bottom

Cut 3mm x 104mm filament for hinge.

Prep parts by drilling out the holes to allow for the filament to pass though unobstructed. Make sure hinge works properly. Let 2mm of filament extrude pass the printed parts. Heat up filament with lighter and melt into King's Toilet Bowl Top. (Trick: heat up the filament and then press against a flat object)

Add Foam tape to the bottom of the assembly
Add string to hole and wrap other end around toilet's handle. Wrap String around the handle twice and tie a knot. Now wrap the string around the back side of the handle. Tie a knot. The wrap around the back side of the handle allows the pulling knot not to slip down the handle :-)

Solidworks files Attached as well :-)