How to get dog pee out of couch cushions!?

I have two Min Pins that are quite insane... lovable cuddly but completely WHACK.... they will go for days/weeks /months without accidents.... they act like good doggies...... then once your confidence is high and without ANY warning and completely quiet....the lil guy Zeus...will just pee on something. Not even alot of pee just enough to make it a lil bit wet.... he gets rushed outside and I clean whatever using a pretty strong solution of OxyCLean & water and suck up the wetness with the mighty lil shop vac....it works great on carpet and there isnt a trace of stain or pee smell. Because if he pee's a shot I soak it with a gallon of the Oxy mix a pint at a time and vac it right up....soak it vac it....soak it vac it and once it is dry there is no trace. THis is good stuff for carpets.....

FOR FOAM cushions.... foam cusions are essentially made of sponge rubber or synthetic sponge material....as such they are much like a huge kitchen sponge.......I am affraid SNAKE is correct.....once urine penetrates sponge you will never ever get it out. as an example...take a brand new kitchen sponge, put one small drop of dish soap on it and then place it under running water and squeeze it until there are no soap bubbles!!! takes about a full day under running water and being squeezed every second to stop making bubbles!!! multiply that by the typical amount your dog pee's and think of how often under the flow of running water now long it would take to get that out of a piece of faom the size of a sofa cushion....not going to happen!! As snake says you will need to cut that cushion off the sofa and soak the cover and replace the foam and sew it back together while it is still wet...then sew it back to the sofa.....
OR try the soak vac soak vac method until you are happy that you cannot smell the urine.....you will run more than a few gallons of water into that cushion before you are anywhere close to "done"
sucks ..... but fixable
good luck