And it can be constant. Pity as he is a very friendly cat and loves to sit on our laps, but as soon as he relaxes, he does the deed and we spend most of our time holding our noses or chucking him off us 
He is a rescue cat and I'm wondering if this is the reason he was left behind when his owners got evicted and took 4 of their other cats with them 
He eats IAMS dry food, but the stink is making me want him to stay outside.