Make sure he is not doing it due to pain in his urethra from crystals forming which could potentially block his urinary tract.
At least he can pee now--- although you may not like his style but to prevent what can be a deadly disease in make cats make SURE you are giving him a high quality wet food preferably organic and home prepared (without chemicals or grains) and only giving it to him twice a day. Do NOT leave any food out all day for him to free feed on. This does something to the brain chemistry and messes up the cat's pH which can affect the formation of crystals. Get Anitra Frazier's book THE NATURAL CAT to learn more. When cats start peeing outside of the litter box or worse....go to the box repeatedly and can't pee much or at all is when things are SERIOUS. Don't let it get to that point. Also keep the stress level down. These urinary disorders attacks are typically brought on by stress. Mixing in drops of Rescue Remedy into his water might help deal with the stress.
I have had 2 cats with this condition and diet is KEY to treating and preventing its onset. It can get so bad if you ignore it by continuing feeding cheap (or even expensive ie IAMS and SCIENCE DIET) commercial or dry food and or free feed, to where the vet would suggest cutting off his genetalia entirely. There is another thread in this forum about that. You DON'T want to let it get anywhere CLOSE to that point. It is well worth it to spend an extra dollar per day on QUALITY wet food to avoid a thousands of $$$ in vet bills down the road. I make my own adding this supplement called Insticts which is a supplement you add to raw meat, water and liver. I make batches, freeze and defrost small portions which last a couple of days in the fridge. Here is the website if you are interested www.felinefuture.com