i read some articles and saw a house doing this. Get bottles and peel off the labels. Add red water inside (the colour like syrup). Put them where the cats like to poo. Try this and tell us what's the outcome.

How?
Spray on the cat?

I parked my car in front of my house, and cover it with blanket.
The problem start with 1-2 feral cat that keep sleeping on my car roof, I have no problem with that, till it start peeing around.
He even pee on my car roof many times.

I have no idea why it keep doing that.

Even my own cat never did that.

I use this spray, not just it smell like piss, it does not work too.

Any other solution?

Please don't give me killing solution.

saw many house do this. those house become cat gathering spots.

daiso have cat spikes.

i read some articles and saw a house doing this. Get bottles and peel off the labels. Add red water inside (the colour like syrup). Put them where the cats like to poo. Try this and tell us what's the outcome.