All my life, I have misused the toilet block: I have hung it on the edge, but it has to be done differently.

Take any block you usually use.

Insert the tethers into the rim. Much must be done to do so.

See now how comfortable it is.

After manipulation, the block holds perfectly and does not disturb. You can move it in any direction. A few days on one side, a few days on the other and under the edge it never gets dirty

Did you succeed?