The - long since demolished - public toilets I used to cycle past on my way home from school had rivulets of spunk dripping down the stall walls.

Of course I always added my young load whilst reading the filthy comments and drawings on the walls

Yes. Tesco supermarket toilet in Gloucester. Disabled cubicle had a big glob of cum on the floor.

did you add yours too it?

Yesss! Early on running down the toilet door

I have seen fresh cum several times in both stalls in public toilets and in/on urinals and on the walls above and beside the urinals in public toilets. In addition I have left multiple loads in stalls and at urinals in public toilets and in airplane restrooms, usually on the back of the folding door or on the side-wall.