Cat peeing on exact same spot in my bed

Don't rub your cats nose in his pee/poo, it is totally pointless.

You need to clean out all traces of smell from that spot on the bed as this is likely to be the reason he keeps peeing on the same spot. If he cannot smell himself/his own pee is far less likely to pee there again. Matress cleaning is a pain in the bum, but a must I'm afraid. Get a solution of biological detergent and warm water and scrub the holy crap out of the matress, pound with a towel and repeat. You could aso use the specalist enzyme cleaners you get in pet stores - both so the same job. Don't over soak the matress as this can lead to mildew growing on/in it. Once you are satisfied it is clean, give it a final rinse with bicarb soda in water to help get rid of all smells. Dry the matress really well (place towels on it and stamp on them until no more moisture comes up - it could take a while) and leave to air dry overnight in a warm place, standing the matress up against a wall to stop more moisture going into it. Wash all sheets, duvets, pillows (whatever is in that spot) in bio detergent on as high a temperature as the insructions allow.

If the cat is still going to the toilet in the same place on the bed after the big clean, it is more likely a behavioural problem (he could be marking one side of the bed) and it would be easier to keep him out of the room when you cannot supervise him.

For my dogs I used a mixed of vinegar and water, I checked for cats and like lorebringer said you need to take out the odor first and maybe then try the vinegar mix.